Also thought that I would add that since this problem appeared "from nowhere" (smelled coolant on startup this morning and saw bubbles in the overflow bottle) that I will also be replacing the cooling fan and checking the relay.

I suspect that the two hours per week day that this car sits in school pickup line is likely contributing to premature failure of the fan.

Hopefully I have caught this in it's infancy. My wife swears that the gauge never indicated overheating but I know how that goes even when dealing with customers.

 

What kind of mileage? You could probably do the serpentine belt service, along with READ and Alternator clutch/pulleys.

 

~126K.

 

Personally I've never heard of a 3.2L that needs a head gasket, especially at that low mileage - how did you diagnose?

 

That, and don't let anyone charge you very much to magnaflux an aluminum head!

 

I have unfortunately found myself in need of tearing down the wife's XC90 to do a head gasket.

How was this diagnosed? Did you use a head gasket leak detector that finds unburned gas in the cooling system and changes the color of the fluid in the tester?

A head gasket on the 3.2 Fomoco engine in not a simple project - I would make sure what you are doing is actually going to fix what you imagine the problem is.

If the car was overheated to the point the head gasket is damaged - the head is going to be warped - and to fix that properly the head will need to be straightened, not surfaced - straightened. A valve job is required after that. You will find many worn/wornout parts during this process - water pump, idler pulleys, one way clutches - And there are several special tools needed to get the cam drive off/on and aligned properly.

Your local machine shop may not have the capability (knowledge) to properly fix this head - especially if they want to magniflux an aluminum head!

 

Your local machine shop may not have the capability (knowledge) to properly fix this head - especially if they want to magniflux an aluminum head!

Magnaflux makes dye for use on aluminum heads (and hydraulic motors, hubs, etc).

So yeah, to be pedantic it is not magnetic particle inspection. We've always called it magnaflux because they sell the dye for Al.

 

R&R the 3.2 head takes various special tools and specific instructions to perform this repair.
I am all for helping, advising and offering advice to anyone here performing any DYI repairs.
Be careful and know what you are getting into. Hopefully others here will offer advice as well.
There are some steps that can not be bypassed or short cut in any repair.
These are just a few of the special tools needed. The engine, timing chain and gears have to be set in time.
Adjusting the valves can take hours to do. The valve buckets are different thickness. You measure and change out
valve buckets as needed to change the clearance spec. You always need new or used valve buckets. What is on the head now can and will change when measuring and adjusting valve clearance.

 

R&R the 3.2 head takes various special tools and specific instructions to perform this repair.
I am all for helping, advising and offering advice to anyone here performing any DYI repairs.
Be careful and know what you are getting into. Hopefully others here will offer advice as well.
There are some steps that can not be bypassed or short cut in any repair.
These are just a few of the special tools needed. The engine, timing chain and gears have to be set in time.
Adjusting the valves can take hours to do. The valve buckets are different thickness. You measure and change out
valve buckets as needed to change the clearance spec. You always need new or used valve buckets. What is on the head now can and will change when measuring and adjusting valve clearance.

View attachment 166408 View attachment 166410

View attachment 166411 View attachment 166412


View attachment 166413 View attachment 166414

 

Okay. I finally had enough time/space/etc to bring the car inside and do the leak down.

I talked about doing this on this car before but never got the chance.

I did not find what I thought that I would find.

Cylinder	1	2	3	4	5	6
%loss	17	18	15	10	15	14

Seems fine for a ten year old car.

Anyway, I did find this on #6

I can't decide if it is coolant burned on or fuel deposits. They chip away easily and the plug is not damaged by the removal. The plug only has about 15k on it.

I am very nervous about putting this car back on the road because my wife and I both saw the coolant reservoir bubbling on Sunday morning right after we started it. Also, I know that I smelled coolant. However, I do have neighbors. I can't swear the smell originated here


Maybe I'm just being paranoid but she's been complaining that the car is underperforming. Like there is a loss of power.

Anyway, these leak down numbers look good to me so I'm going to pressure test the cooling system and go from there.

Hopefully it is good because it's getting late and I'm ready to rest.

 

I can't decide if it is coolant burned on

As another has mentioned - if coolant is burning in a cylinder - everything will be steam cleaned, and very clean - no carbon, no deposits. Also it's most common that if a head gasket is damaged due to overheating - the middle cylinders will be where the head gasket breach is.

 

I just realized that I have no way to test the reservoir cap.

Could a bad cap allow the reservoir to bubble while the engine is warming up?

I bet that a bad cap would allow me to smell coolant.

 

There are test kits you can get to prove the presence of combustion byproducts in the coolant.

If you're getting coolant into the combustion chamber I'd expect the plug to be steam cleaned.

Are you getting any white smoke out of the tail pipe? Do the radiator hoses get rock hard?

 

There are test kits you can get to prove the presence of combustion byproducts in the coolant.

Yeah, I don't care for those. We quit using them in our fleet maintenance because of reliability issues.

If you're getting coolant into the combustion chamber I'd expect the plug to be steam cleaned.

Probably so. I included the pic because it was the only problem that I actually found. I'm going to guess it is fuel then. Hopefully it is not an injector issue on that cylinder.

Are you getting any white smoke out of the tail pipe? Do the radiator hoses get rock hard?

Nope. Like I said, we started the car on Sunday morning and while getting everything situated, I smelled coolant. I am well trained to smell coolant as I work in an industrial setting repairing equipment that is abused daily.

Anyway, the bubbles in the coolant reservoir are what really got me worried.

I have only ever noticed the combination of errant coolant smell and bubbling reservoir when there is a leaking head gasket or a problem with the head or a liner.

I did finally realize that a bad cap would definitely allow for phantom coolant smells. What I asked and haven't found an answer for is whether a bad cap would allow the reservoir to bubble.

 

After reading this thread, that leak down isn’t bad.

• With the smell of coolant, has external coolant leaks been observed?
• Was the coolant smell only by the engine and not the tailpipe?
• Obviously, does the oil smell sweet?
• Have you lost coolant?
• If you are thinking about doing the serpentine and water pump, was the coolant system never done? I recommend doing it at 100k miles not the Volvo 150k miles.
• Have you observed the coolant temp with an OBDII reader for perhaps a sticking or partially sticking thermostat? What is the original cause of the overheating if it happened?

Coolant leaks to observe, such as under the intake manifold by the oil cooler and thermostat. You can also get incomplete sealing of the small coolant hose right on top of the intake manifold. Also, check the heater hoses in the rear.

I have recommended and linked videos in the past with other 3.2 owners for the combustion gas test in the coolant reservoir. I don’t see why that’s not an option. The main issue I see with it is using a good tube and suction and if you don’t get a color change, double check it works at the tailpipe. For a cheap test, it’s worth it to help gain a fuller picture.

Lastly, if you are still having trouble with confirmation of a head gasket, you can get an oil analysis. There should be more sodium in the oil with bad head gasket and coolant getting into the oil….that is if you don’t live close to a coast with salt water in the air.

 

Thought of a few more issues or concerns and why confirmation of a head gasket is imperative before going down the rabbit hole.

The thing with this aluminum engine is the valve cover is also the camshaft bearing caps. Thus, if the head is warped, will the valve cover/bearing caps be aligned after unbolting it and if it isn’t aligned, is reaming for alignment even an option? That’s just one issue to think about and why shops would rather drop the front subframe and swap a good sealed lower mileage used engine.

I have not taken apart or rebuilt this 3.2 engine, but I have done a number of engines over the decades. Always prepare for the worst and budget if the worst may happen whenever you open an engine up. You should not put an engine back with worn or bad parts after you are in there. You mentioned the valve seals, but what about the camshaft bearings, dropping the oil pan to inspect parts and bearings if water got into the oil, etc.

 

You should not put an engine back with worn or bad parts after you are in there.

Well, that's the reason for my inquiry. I was wondering just how far down the rabbit hole I should be prepared to go based on the experience of anyone having done this before. It kinda looks like the answer is engine out, full rehab/rebuild. I'm thankful it doesn't look likely for me at this time.

I am fully aware that this is not a b230 or an I5. If it were, I'd know better how far to expect to dig.

Anyway, thanks for your help.

 

One more thought regarding the bubbling that I witnessed.

A coworker suggested that I may have a sticking thermostat.

I've thought about that and it seems possible that a stuck closed thermostat could allow the coolant trapped behind it to condense after being shutdown the day before and leave an air pocket (or at least a low pressure region) that would draw coolant into it after startup the next day.

This really makes the bubbles make sense in my mind - especially since the bubbles were coming up from the outlet at the bottom of the reservoir. It looked more like an improperly bled cooling system burping than the kind of bubbles you see during an overheat condition.

Anyone have arguments for or against this theory?

I'm probably just going to order a thermostat and cap for this car today.

Anyway, let me know what you think.

 

Yes, I mentioned the stuck thermostat too. Stick an OBDII reader on and observe the temp as this can help with diagnosis. Also, ensure the fan will turn on from low to high so it doesn’t overheat while sitting.

You have to still understand why and if the engine overheated and your coolant components that should have been replaced by 100k miles are primary suspect. Blown head gasket is not a spontaneous issue we see in a 3.2.

In post #19, I ask questions, such as have you looked for coolant leaks, to have you lost coolant (even if little over time), to if you have done the coolant system maintenance.

Without even looking under the intake manifold, around the oil filter area, for coolant leaks or seepage, you are pretty eager to jump into a head gasket job. I wouldn’t have spent the money on engine specific tools unless I at least had the leak down and combustion gas in coolant reservoir test done.

 

If replacing the t-stat, also replace hose 12 and o-ring 26. The hose goes from the engine block to the oil filter housing.
The hose will crack from the inside out and leak. The plastic end that goes into the block will crack and crumble. Hose 12 only, does not include o-ring 26.

1 Thermostat kit 1.00 31355151
2 Gasket 1.00 30650891
3 Temperature gauge kit 1.00 30750926
4 O-ring 1.00 30713577
5 Temperature sensor 1.00 NS
6 Clip 1.00 30713576
7 Thermostat 1.00 NS
8 Thermostat housing 1.00 NS
9 Coolant pipe 1.00 31269037
10 Coolant pipe 1.00 31293052
11 Six point socket screw 4.00 986216
M6x25
12 Hose 1.00 30713530
13 Coolant pipe 1.00 30650741
REPL 1 PCS 31219144, 1 PCS 30792933
Coolant pipe 1.00 31219144
14 Six point socket screw 4.00 986318
M7x20
15 Hose clamp 1.00 988027
16 Hose clamp 1.00 988024
17 Hose clamp 1.00 988027
18 Gasket 2.00 30650776
19 Flange screw 2.00 982757
M6x16
20 Six point socket screw 2.00 986214
M6x16
21 O-ring 1.00 982292
22 O-ring 1.00 975667
23 Hose clamp 1.00 988024
24 Nipple 1.00 31293434
25 Flange screw 1.00 982776
M7x20
26 O-ring 1.00 982292
27 Screw with pin 2.00 986697
M7x17x40
28 Water pump kit 1.00 31219000
29 Water pump 1.00 NS
30 Sealing ring 1.00 30788237
31 Flange screw 6.00 982776
M7x20
32 Coupling 1.00 31219096
33 Clutch 1.00 NS
34 Spacer 1.00 NS
34a Spring 1.00 NS
35 Guide pin 1.00 30750804
36 Hose, thermostat 1.00 30774512
37 Hose, return 1.00 30774513
38 Hose, outlet 1.00 30774514
39 Inlet pipe 1.00 30650738
40 Six point socket screw 2.00 988507
M6x14
41 O-ring 1.00 976045

 

Of course it’s your money and your time. Also, don’t read into our questions too deep as proper diagnostic procedures will be asked so that people reading in the future can understand the proper methods and what to look out for. Each person’s post for help is another’s lesson.

You mention fleet vehicles and you don’t trust the combustion gas test. That’s your judgement and there are good, as well as not so good, test kits out there. I treat all my vehicles like fleet vehicles, meaning religiously maintained, maintained before the recommended service, and do preventative maintenance, to prevent my cars from needing a tow truck and preventing them from being off the road for an extended time. The cooling system on your XC90 should have really been done by 100k miles and this preventative maintenance could have prevented an overheating issue resulting in a much larger head gasket issue.

Basically, if you want to focus on what to do while in there and saying you know how to wrench on cars then you should know to look at everything in renewing or replacing. At 120k+ miles, normal wear happens. It’s really a matter of cost and time that limits rebuilds, this will dictate the prioritization of what will get replaced.

Btw, I never buy specialty tools unless I need them, especially engine specialty tools. There’s a saying about holding inventory that’s unused or unsold….it’s just money sitting on a shelf that devalues over time. When it comes to tools, money spent on a specialty tool not being used could have been used to pay a bill that accrues interest.

 

You mention fleet vehicles and you don’t trust the combustion gas test. That’s your judgement and there are good, as well as not so good, test kits out there. I treat all my vehicles like fleet vehicles, meaning religiously maintained, maintained before the recommended service, and do preventative maintenance, to prevent my cars from needing a tow truck and preventing them from being off the road for an extended time.

Our fleet ain't like that, lol. I assist in the daily performance of the largest package sorting operations in the US (and probably the world). It is a controlled demolition derby. Not to take away from your fleet experience but I'm afraid we have had vastly different experience on this matter.

Back to Volvos... I have only owned this car for about twenty thousand miles. I have replaced the windshield, bought keys (only came with a valet key), repaired several wiring gremlins, bought tires and replaced the thermistor in the climate control module.

Other than that, I managed to buy my first home and re-establish my tool inventory at work and at home. I have not even had a place to safely store expensive tools until this spring.

The cooling system on your XC90 should have really been done by 100k miles and this preventative maintenance could have prevented an overheating issue resulting in a much larger head gasket issue.

I bought the car at 105k. We had no records with the car. I got a clean title, a valet key and a Carfax that the owner thought was important so I took it.

I have worked (on average) 55 hours a week for the last three years. Perhaps you know how little time there is to be proactive when working like this and being an active, involved husband and father? I will start trying to plan the work out in front of me now that I have a garage and storage space for parts and tools.

Btw, I never buy specialty tools unless I need them, especially engine specialty tools. There’s a saying about holding inventory that’s unused or unsold….it’s just money sitting on a shelf that devalues over time. When it comes to tools, money spent on a specialty tool not being used could have been used to pay a bill that accrues interest.

Maybe. Time is also money. What shape do you think I would be in if my wife didn't have her car this week? Sure, I could have rented a car. But, I had the tool on hand to perform the leak down test. Seems to me that this tool already paid for itself.

 

Just a side note- if you're looking at the I6 behavior, expand your search to include other models with this motor (see Volvo SI6 engine - Wikipedia for a list).

Having prepositioned some specialized tools for your motor, next is a copy of VIDA and a DICE if you don't already have one. It's handy for all sorts of diagnostics and is the technical resource "standard". See OBD, CANBUS & Engine Management | SwedeSpeed - Volvo Performance Forum for some information, at least give you an idea as to what it is (pre 2015).

 

The bubbling is a concern. The most common reasons for that are localized boiling of the coolant or a leak from the combustion chamber to the cooling system.

If the engine wasn't hot when you saw the bubbles, that does point toward the latter. However, no white smoke and no steam cleaned cylinders, so it's still up in the air.

If the thermostat were sticking the temperature gauge should give you an indication.

In a different life I worked on a model of car that for several years was plagued with bad cylinder head castings. The first thing that would happen is air would get trapped in the thermostat housing where the temperature sensor was. The temperature would go to about 3/4 on the gauge and stay there. The trapped air was hot enough to open the thermostat but not hot enough to send the gauge to the top.

I don't think you mentioned whether or not it is loosing coolant. At this point, I'd top up the cooling system, purge any air, and take it for a ride. The combustion gas test can't do you any harm and would give you one more data point. If after the ride the radiator hoses are hard as a rock, you can bet that, somehow, you've got a combustion gas leak.

 

I put a very small quantity of Volvo coolant in the reservoir (left over from the heater core on my S60). Maybe a half quart total. First time topping off the coolant. The oil on dipstick and cap were clear. No indication of mixing.

Maybe I will have to drive her car for the rest of the week so that I can observe the gauge and monitor with my scan tool.

 

I don't recall if you mentioned it or not, but have you tried putting compressed air into the cylinders and looking for bubbles? It wouldn't be as immediate or dramatic as if it was running, but it might help bring things into focus.

 

I only did the leak down test. I also fastened a latex glove to the reservoir opening in the hopes I would see it move (kind of like old blow-by test for b230s). I got nothing.

 

We all have our reasons for time and money. You don’t have to prove yourself in this forum when it comes to your life or the decisions you have to make. However, if you want to make claims then yeah, we ask questions for a clearer picture.

Btw, if I worked 55hrs and have children and a new house, I personally would make sure I needed a new head gasket before jumping in. I would exhaust all diagnostics because a wrong diagnosis could mean months to complete the job and weeks of preparation researching and doing spreadsheets of parts & outside labor.

Let’s get back to the only observed indication for the decision, the bubbling. The coolant reservoir has 3 hoses connected to it. Did you observe bubbling coming from the main lower hose or are you observing bubbles coming from coolant flowing from the upper hose? (Edit for clarification: coolant from upper hose flowing into the reservoir, creating bubbles as coolant pours in)

Another note, you might not know your engine overheated or has a sticky thermostat just by the gauge coolant temp. Industry wide, manufacturers use a central tendency type of gauge where the coolant temp can fluctuate with the gauge needle staying in the middle. Why? Because it’s normal for the coolant to fluctuate in temp and people would go to the dealership saying their car overheats when it doesn’t. That’s why you won’t know if you are overheating until the needle shows overheating and you get a dash light.

This is why it’s important to read the coolant temp on an OBDII reader. A decent cheap Bluetooth one can be bought on Amazon for less than $40. The live coolant data should fluctuate between around 185F to 195F. At ~195F and sitting you should hear the fan go on high with the A/C on, accounting for an 85F day. If you are somewhere between 200-220, then that’s an issue.

Again, seems like a basic question, but I’ll ask for a 3rd time. Have you looked around for coolant leaks or seepage, especially around the oil filter housing and thermostat area? There are YouTube videos on the old thermostat leaking or seeping from the gasket o-ring. There are threads here showing the old o-ring and plastic connector for the small coolant hose to the oil cooler can seep. These can give a coolant smell and slowly leak coolant as you have mentioned. O-rings are used in several places in the 3.2 coolant hoses and these could also seep without a sprung leak. (Edit for clarification: this is why it’s important to do cooling system maintenance as old rubber is old rubber on any vehicle)

 

Let’s get back to the only observed indication for the decision, the bubbling. The coolant reservoir has 3 hoses connected to it. Did you observe bubbling coming from the main lower hose or are you observing bubbles coming from coolant flowing from the upper hose? (Edit for clarification: coolant from upper hose flowing into the reservoir, creating bubbles as coolant pours in)

The bubbles were small and following the path that I marked on the image below.

This is why it’s important to read the coolant temp on an OBDII reader. A decent cheap Bluetooth one can be bought on Amazon for less than $40. The live coolant data should fluctuate between around 185F to 195F. At ~195F and sitting you should hear the fan go on high with the A/C on, accounting for an 85F day. If you are somewhere between 200-220, then that’s an issue.

I have a Zurich ZR15 scanner that I bought from Harbor Freight that is pretty nice. It can read all (I think all) of the modules on the XC90. It also reads the ABS and SRS data as well. I will try to watch the live data but I will have to drive it to work to do that (wife will be sad, lol).

Again, seems like a basic question, but I’ll ask for a 3rd time. Have you looked around for coolant leaks or seepage, especially around the oil filter housing and thermostat area? There are YouTube videos on the old thermostat leaking or seeping from the gasket o-ring. There are threads here showing the old o-ring and plastic connector for the small coolant hose to the oil cooler can seep. These can give a coolant smell and slowly leak coolant as you have mentioned. O-rings are used in several places in the 3.2 coolant hoses and these could also seep without a sprung leak. (Edit for clarification: this is why it’s important to do cooling system maintenance as old rubber is old rubber on any vehicle)

I visually inspected the engine several times. Hot, cool, pressurized with tester, etc. I never noticed any coolant leaking. I also see no residue from historical leaking at any joint, hose or fitting. I did not notice coolant smell in the cabin at any time either. There was no coolant on the ground after the vehicle sat for 30+ minutes pressurized with a coolant system tester.

The only place that I find questionable seepage is the right front corner of the head gasket (on the #1 cylinder). I feel that this is most likely oil residue that is possibly from some previous oil change though.

 

Just a side note, let us help you figure out if you do NOT have a problem so you can save time, money, and any anxiety something is wrong. The questions are for good reasons and if you don’t want to perform some of the diagnostics, especially when they are much much cheaper than a head gasket job, then it may appear you want to jump in more than solve the issue, if there is one.

If you don’t have a head gasket issue, then you can spend that money on engine maintenance, transmission fluid, and perhaps suspension maintenance/upgrades so your XC90 can keep on going until 200k miles.

 

If you do decide to pull the head, post pictures so that we can follow along.

 

So you ran it with a rubber glove on the coolant reservoir, and the glove did not inflate? That would seem to refute the idea that air is being introduced into the system. Did you see any bubbling during that time?

 

I didn't actually start it like that because it was inside my garage. I probably should have backed it up but I had it on jackstands with all plugs out. I took the glove off of the reservoir when I got done with the leak down test while I was putting everything back together.

But yeah, I agree all of the evidence is saying that there's no way it is a head gasket. But what about the bubbles... 🤔

 

Those thermostats are prone to coming apart. I'd replace that before all this over thinking.

 

Prone when they aren't changed. Not sure why Volvo and others think cooling system parts should not be changed between 80-100k miles as it is with every other vehicle.

 

Confirm the fan works when it should. Then you will know if you need to add it to the list.

If you are going to do the water pump, then you are doing cooling system/serpentine/decoupler. These are all 100k mile maintenance items. Add the PCV while at it.
You can read the 3.2 thread: The 3.2L (B6324S) Engine: The Good, the Bad, and the...