Head gasket; what else?

Seems like the ongoing coolant loss I have been experiencing must be a head gasket leak creating vapor bubbles in cooling system and pushing coolant out overflow.

Question for group: if we have to tear down to head gasket, assuming block & head are ok, what else makes sense to replace/clean/check in the process?
Wagon has 127k miles, balance shaft delete, new egr cooler, egr cleaned 15k miles ago, lower turbo hose replaced recently and no performance problems or concerns (other than coolant loss). Camshaft at 90k with timing belt.

I hope to get another 100k out of this over the next 5 - 7 years, and I'm ok with spending a bit more on this project if there's other things that would make sense to change in the process.

thanks for your input

Brian
Oly, WA

First replace the thermostat just for good measure. Next bypass the EGR cooler temporarily and see if your coolant loss stops. Both are easy and cheap things to do before removing the head.

I am having the exact same problem. Short summery:

Tried EGR/Cooler delete. Replaced thermostat with tested OEM. New reservoir cap. I was thinking about replacing the tank but am looking for a pressure tester w/ fitted cap to borrow first.

One thing that tripped me and my mechanic out is that coolant doesn't flow through the return line back into the reservoir. Someone else, another mechanic, told me this is normal for our cars.. Can anyone else chime in on this? Is it a blocked cooling passage vs head gasket?

(7,000 miles ago, I did the timing belt/water pump change. This seemed to make the problem go away for awhile, still some coolant loss but manageable. Now I can't get down the road.) Not overheating but loosing a whole tank of coolant in a very short amount of time..

PS if you want to buy my used EGR kit for less than new, PM me. 50 miles or less on it.

Do you have hydrocarbons in the coolant? If you don't know, test it.

bad new egr cooler?

The EGR cooler was replaced 7 months ago....I suppose it is possible it was bad out of the box? Agreed to change EGR cooler when problem 1st was apparent due to an attractive barter deal, but it did nothing to eliminate issue. Felt I could cross that off the potential suspects.

Can see residue spatters in area below coolant tank overflow. Thinking of trying to rig a hose to that outlet to capture and do hydrocarbon test on the fluid pushed out in an attempt to verify exhaust gasses present.

Reservoir itself shows not Hydrocarbon signs, oils shows no sign of coolant. Vexing.

Brian
Oly, WA

Can anyone recommend a reliable test kit for hydrocarbons in the coolant?

Also BHW owners: Do you get coolant flowing through return line to the reservoir at idle, and w/ 2,000-3,000 RPM?

test strips + return

Don't know where mechanic buys, but uses strips that look similar to the ph strips used in science class last century. Color changes (or not) based on hydrocarbons present (or not).

I have never observed fluid return to reservoir unless pressure is released - then it comes racing back. Of course, absent an under hood cam, I have not observed fluid being drawn out of the reservoir either! Don't understand where/why it goes - I've been told hose expansion, but c'mon, practically a whole reservoir? I don't buy that.

Typical scenario for me is that after 200 - 300 +/- miles on a trip low coolant light comes on. Open hood, maybe an inch of coolant in bottom of reservoir. Slowly open, coolant rushes in, typically to, or just above minimum line (was at seam at beginning of trip with heater hose pulled back to try to get all air out). Coolant loss in 400+ mile trip between Oregon & WA is 300 to 400 ml.

Odd, but loss seemed less on a recent trip when I did not dilute G12 when filling before I left. On previous trip, I had topped with 1:2 (coolant/water) due to low supply and no threat of cold weather. Figured it would mix itself to 1:1 when adding undiluted.

Brian
Oly, WA

Have you checked replaced the coolant flange on the back of the head? Common to leak

Thanks for the tip - yes, I've used a little mirror to check that area. I wish that was the issue!

Pretty certain now it is head gasket, as all signs point to vapor bubbles - after changing tank (previous had questionable seal), now visible dried residue in splatter pattern below outlet on expansion tank. Going to try to jury-rig a catch can for the blow by to test for hydrocarbons. Just have to get the time to hook that up.

Just don't know what else could cause the symptoms described above and in other posts.

Brian
Oly, WA

other ideas?

Ok everybody, one last shot at this - Please!

What, other than some type of head gasket or head issue, *could* produce air bubble in coolant system forcing coolant out reservoir overflow on a regular basis?

Note: drove around after warmed up and after coolant tank topped to seam and connected VagComm & computer; never went above 96c in temp, generally around 91c in approx 25 to 30 min.

a) bad thermostat
b) bad radiator circulation
c) bad luck
d) (fill in blank)

If there is a head gasket issue but no coolant in oil, etc, is it possible that there has not been damage to a piston or pistons?
Any suggested tests before head gasket job?
Other things to change/replace/inspect along the way?

Thanks for any help/suggestions

Brian
Oly, WA

A stuck thermostat will boil the coolant. A cracked head or cylinder would let combustion gases into the coolant. Test to seeif there is hydrocarbon in the coolant. Most parts stores sell the test kits. If it's hydrocarbons then combustion gases are getting in there. If not, then you problem is elsewhere and possibly a good news.

I went through this a couple years ago, never overheated but coolant ejected through the overflow hole. Oil always looked normal, sniff test on coolant negative. Blocked egr cooler, no change. This went on several months, finally Frank took head off, #2 and 3 were washed clean on the manifold side.

Head gasket leaks are sneaky, but your situation is just like mine; might be time to look inside

What do you mean by #2 and 3 were washed clean on the manifold side?

Thought the same thing - I assumed it meant the gasket was practically absent or blown out there.

Just ordered a HC test kit to do it myself to double check. Hoping for intermittently stuck thermostat. Have had some intermittent odd temp spikes while going up a few long grades.

Brian

Head gasket or EGR cooler the two failure items that cause this, in my experience.

A couple of years ago, there were several head gasket failure threads in the B5 forum over the course of about three months. I'd still consider it uncommon, but it's definitely a failure method that we've seen here several times before.

Washed clean is the way the top of the pistons looked on the manifold side. Normally they have a dark combustion chamber appearance. The pressurized coolant did that. The area of gasket defect was very small. But mighty!

96Brian said:

Thought the same thing - I assumed it meant the gasket was practically absent or blown out there.
Just ordered a HC test kit to do it myself to double check. Hoping for intermittently stuck thermostat. Have had some intermittent odd temp spikes while going up a few long grades.
Brian

Click to expand...

A leaking head gasket can't let coolant into the manifold unless it get's burnt up in the combustion chamber. For that, almost all of it would go out the tail pipe. So I'm having a hard time understanding how the manifold is washed.