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634 Posts
Discussion Starter · #1 · (Edited)
While ID'ing a small coolant loss ( likely heater core), I developed a larger coolant loss. I do believe I have a leaking heater core, but in the interim I found this.

First I observed a puddle of coolant under the car in the area of inside from the RF wheel, this was not happening previously. Did not seem consistent with a heater core, either volume or location - it was a couple of ounces I estimate. It drops a few ounces and then stops each time the car is run and then parked.

Crawling underneath today, I took more pictures and exposed the water pump. Water pump is dry top and bottom, the coolant reservoir is not leaking (is new), radiator is also new and not leaking.

Is this a turbo cooling line issue? It does not seem to be leaking in the right place for that.

Turbo from underneath. Little bit of oil but no obvious coolant, or puddle underneath.

Most of the coolant is pooling on the oil filter cap/adjacent pan bottom and then dripping down. Puddle is centered under here.

Water pump is dry from above and below. PS reservoir is pushed aside and looking down past the intake camshaft.

Could it be this line (what is it?)? It's right beneath the crankshaft pulley. This is looking from the wheel well over the subframe at the crankshaft pulley. Leak is at this level and no higher anywhere.

Water pump from beneath, nothing wet below it until you get down to the oil pan level.

634 Posts
Discussion Starter · #2 ·
Hello Wetness, my old friend. I've come to banish you again...

Finally got this figured out - the upper radiator hose can leak in a way you cannot see from above and then it all manifests itself down below to mislead you. I'm gonna explain because I found some people complaining of the same symptoms in old threads, but no clear answer. Maybe this will save someone else time or expense in the future.

I figured it out last night lying in bed thinking about it. The car was losing right at 4ozs of fluid each time. Which told me it was emptying a consistent space/volume in a hose or housing somewhere. I also noticed it did not do it yesterday after I started it, ran it, but did not drive it. Which told me it might be thermostat dependent as I likely didn't get the thermostat open. Leaving the upper radiator hose as suspect #1, and possibly the t-stat housing/gasket.

This morning first thing, I went and used a flashlight to look very carefully around the t-stat down between the thermostat housing and the intake manifold and found our dreaded friend - wetness. Eureka. Pic below on where to look.

What happened was due to an over-abundance of caution on my part when doing the radiator. I did not remove the upper hose from the t-stat housing. I just loosened it and pivoted it upward - then put a paper towel in the free end. This was to prevent any debris or anything entering the t-stat housing while I worked - I was trained to always be paranoid about open orifices to closed systems - pistons, intake manifolds, etc. Minimize exposure and block openings while working nearby.

That loosened accumulated debris in the lands/grooves of the t-stat side of the upper hose. The radiator side was clean and free of debris and in good shape - I inspected that and assumed the other end would be likewise. Nope - these OE Volvo hoses are not very robust to begin with and age poorly. I cleaned up the hose thoroughly and re-assembled it and it works fine now. I ordered a new, better quality, and I will pop that in soon.

Ok, now back to fixing the heater core, dash mounts, and then refinishing the Perfo wheels for summer tires. (I am really ready to get this thing done...)

If you have this problem, do this:

If you have an unknown leak like this, look down here between the upper radiator hose/t-stat housing and intake manifold. It drips down there without leaving a trace on the hose or housing. Hard to find. (It is wet down there, just hard to see as it is out of focus).

The heat from the t-stat housing causes the EPDM to degrade over time, and the hose is not terrible robust/well built to begin with. Removal/reinstallation without thoroughly cleaning the loosened debris can cause this leak.

Cleaned up hose goes back in and works ok, but next step is a better grade of hose.
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