Overheating Issues

PassionRed91 · Apr 16, 2015

ElementR said:
I still suspect you were leaking coolant allowing air to accumulate, locally expand and cause both your coolant temp spike on the gauge as well as venting through the pressure cap... very common with leaks. If your thermostat wasn't working, your upper radiator hose/radiator would have never got hot... now if you perceived them to be hot and they actually weren't, that's a different story.

Good move on the system flush. Did you have any gel like substance in the coolant? If you had incompatible coolant in there, you could have allowed silicates to drop out and contaminate the system. That can also plug radiators and heater cores. Keep that in mind should you experience further cooling issues. Many people don't realize that not all coolants are compatible and color alone doesn't mean a lot... need to follow the manufacturer's spec

Interesting with the expansion tank disintegrating. How so?

:facepalm: well I did run prestone when I swapped out my turbo, so i highly doubt I was following manufacturers specs and therefore probably contaminated the system. Ill upload a photo in the AM to show what was floating in my coolant expansion tank. As for my upper radiator hose, it was hot, but it could have easily been because every time I grabbed it the engine had been running for a while, and therefore could have been just very hot to the touch. While I was in there I also swapped out all of my coolant hoses.

I appreciate the help!

dougy · Apr 16, 2015

im glad it worked out for you...when you did carbon in coolant test, was your engine fully warm and running when you did the test?

reason why I ask is I see black soot around your cap...kinda unusual.

StealthyS60R · Apr 16, 2015

i saw that too but had assumed it was just the result of a dry rotting reservoir cap gasket. That being said, the OP should check to be sure the cap seal is still good, if it leaks and can't maintain pressure it may be adding to or causing his issues as well.

PassionRed91 · Apr 16, 2015

dougy said:
im glad it worked out for you...when you did carbon in coolant test, was your engine fully warm and running when you did the test?

reason why I ask is I see black soot around your cap...kinda unusual.

Yes it was. I warmed up the car for about 20 minutes until the water temp gauge on the dash was in the middle and my obdII was reading a little above 200 degrees. I then placed the plunger on top of the reservoir while the car was running and pumped the ball for 2 minutes continuously

PassionRed91 · Apr 16, 2015

StealthyS60R said:
i saw that too but had assumed it was just the result of a dry rotting reservoir cap gasket. That being said, the OP should check to be sure the cap seal is still good, if it leaks and can't maintain pressure it may be adding to or causing his issues as well.

I will definitely check this out. I too was curious as to what the deposit is. My cap and seal appear to be in good condition

JCN · Apr 18, 2015

PassionRed91 said:
Well, this thread has a happy ending ! After receiving my new thermostat and installing, my overheating issue has seemed to fix itself. I am going to do some further investigating (aka boiling the thermostat) and seeing at what temperature it opens up at. My coolant (although I replaced it about 25,000 miles ago) was in very rough shape. Upon further investigation, I noticed that my coolant expansion tank seemed to not only be leaking, but also starting to disintegrate! I decided to replace that as well. Did a complete flush (twice) with DI water before refilling with volvo coolant 50/50. Running like NEW!!!!

Dude that is awesome. I used to only use the mercedes factory coolant in my saabs because of this guy: http://townsendimports.com/Web/cooling_system_folder/coolingsys.htm

"It is phosphate free and pH buffered with inhibitors to aid in the prevention of electrolysis. When servicing cars that have been using it, the difference in the appearance of the internal cooling system is noticeable. Upon thermostat replacement, the aluminum is not covered with the white aluminum oxide or pitted from electrolysis as is common with the green coolants routinely used by some."

The old green (prestone) is not compatible with HOAT coolants. When mixed w/ the blue volvo or and HOAT pink/yellow etc it *will* create pure evil!

ElementR · Apr 19, 2015

I don't know much about the MB coolant, but yes coolants are not formulated the same and irrespective of whatever color they are, you do not want to mix them without being certain of their compatibility. When in doubt, chose OEM. The extent of problems I've seen in my career caused by mixing incompatible coolants is amazing.

EricTheRed · Apr 19, 2015

Look into zerex coolant

PassionRed91 · Apr 22, 2015

ElementR said:
I don't know much about the MB coolant, but yes coolants are not formulated the same and irrespective of whatever color they are, you do not want to mix them without being certain of their compatibility. When in doubt, chose OEM. The extent of problems I've seen in my career caused by mixing incompatible coolants is amazing.

I forgot to answer your last question about the gel like substance. Although there was none in my radiator hoses, there was this white/brownish gel that was starting to accumulate at the hose connections in the hard pipes.

StealthyS60R · Apr 22, 2015

If the gel not just corrosion hydrates, it might be stop leak someone put in the system at one point.

PassionRed91 · Apr 24, 2015

spinall4 · Apr 24, 2015

JCN said:
Dude that is awesome. I used to only use the mercedes factory coolant in my saabs because of this guy: http://townsendimports.com/Web/cooling_system_folder/coolingsys.htm

"It is phosphate free and pH buffered with inhibitors to aid in the prevention of electrolysis. When servicing cars that have been using it, the difference in the appearance of the internal cooling system is noticeable. Upon thermostat replacement, the aluminum is not covered with the white aluminum oxide or pitted from electrolysis as is common with the green coolants routinely used by some."

The old green (prestone) is not compatible with HOAT coolants. When mixed w/ the blue volvo or and HOAT pink/yellow etc it *will* create pure evil!

ElementR said:
I don't know much about the MB coolant, but yes coolants are not formulated the same and irrespective of whatever color they are, you do not want to mix them without being certain of their compatibility. When in doubt, chose OEM. The extent of problems I've seen in my career caused by mixing incompatible coolants is amazing.

I was actually doing research on coolant as my R's have been fine, but my 300ZX TT has been a mess of the cooling system. For a while every time I drove it, it sprung a leak. The previous owner had the car serviced at the dealer and they neglected the hell out of the cooling system.

I found the same thing about the MB coolant being super good at not eating rubber hoses ect. I did some more digging, and Volvo uses pretty much the same formula as MB. Infact pentosin NF which is what coolant we are supposed to use in the Volvo's is actually also recommended for all years MB. We already have our cars filled with it from the factory.

I'm going to work on converting over opmy other cars now to pentafrost NF.

PassionRed91 · Apr 25, 2015

Does anyone if there is another drain for the coolant besides the lower radiator petcock and the head petcock? When I changed out my coolant, surprisingly with these two ports open I was only able to feed the system about 5.2 liters of 50/50 mixed coolant.

ryanlamark · Apr 25, 2015

There may be a block drain somewhere. Who knows if it is accessible though.

spinall4 · Apr 26, 2015

Pop one or both of the coolant hoses off the heater core where they connect to the firewall. I was able to get a bunch more coolant out when I did this on mine.

StealthyS60R · Apr 26, 2015

There is a block drain on the back of the motor on the hardline water manifold that goes down to the oil cooler.

StealthyS60R · Apr 26, 2015

PS - Even when you use all the proper drains, due to the design of the block there will be a bit of water that won't drain out of the water jacket.

ElementR · Apr 26, 2015

^ Yep, use the block drain as you will get far more coolant out this way. You can also help purge out more by pouring in a few gallons of distilled water to displace what's in the block. Image of your expansion tank above shows what appears to be silicates dropping out of solution, although would have to be tested to be certain. Hopefully they didn't plug up your heater core or radiator as they often do when dropping out of solution. Someone likely put the wrong coolant in your system at some point. Good to flush it well now and fill it up with the right stuff + distilled water.

Overheating Issues

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PassionRed91

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