Still overheating - 98 V70 T - sudden coolant loss

broken08 · Post by **broken08** » 06 Mar 2016, 17:01

Ok, I give up. Why is it still overheating!?
98 v70 turbo awd. New TD0419t turbo with stage 3 ARD tune, timing belt done by PO 15k ago. Unknown (but assumed) they did water pump.
I have replaced: Thermostat, ECT sensor. I have filled up the reservoir. Warmed and cooled like 4 times until it stopped getting lower. I did multiple pressure tests, reclamped a few hoses until it would hold 20psi (about double what you need to try) for an hour+. Tightened a few leaky hoses which hold now.
So now, it will be fine a few days, coolant won't be any lower at the end of the day, but then on day 3 of commuting (twice this has happened) it will suddenly have a coolant loss, then even after topping up at work will be overheating by the time I get home 45 mins later. And once cooled it will be empty in the reservoir (but some may have boiled out).
I have left the pressure tester on when running and it doesn't increase, therefore the head gasket is not leaking (at least not badly)
I took the new thermostat back out, it opens around 190 on my stove.
I cranked for a couple seconds with the thermostat cover removed, coolant shoots out so the pump works.
My OBD says temps range 190-220 max after a long turbo run.
The engine fan works, though not sure what temp it's supposed to come on at, I'd assume sooner.
I'm using basic green coolant (safer for aluminum than orange). Does that boil at too low a temp in these?
WTF!?!

Post by **abscate** » 06 Mar 2016, 18:24

No traces of cooolant anyhwere in the engine bay??

Post by **RussB** » 06 Mar 2016, 18:52

Head gasket?

Post by **cuhfs** » 06 Mar 2016, 19:07

Combustion Leak Detector sometimes auto parts stores have loaners

Post by **j-dawg** » 06 Mar 2016, 20:43

reservoir cap? you want the green OEM part

Post by **RussB** » 07 Mar 2016, 07:57

cuhfs wrote:Combustion Leak Detector sometimes auto parts stores have loaners

Best answer so far!

If you can't see any coolant, and it doesn't smell in the cabin and the carpet is dry, it's likely going out the tailpipe

broken08 · Post by **broken08** » 30 Dec 2016, 20:00

The shop I took it to states they performed a combustion gas test in the coolant without findings.
This car is the freaking devil. First $2000 takes it.

broken08 · Post by **broken08** » 30 Dec 2016, 20:03

Since that post I have ALSO done the timing belt, water pump, radiator, heater core, OEM thermostat and blue coolant, coolant reservoir and cap.
Guess what? SAME F'ing PROBLEM!!
It seems pressure will build up in the cooling system and then cause the cap to spit out fluid. It won't do it the first 15 mins or so, but at some point, the system gets charged with pressure. So there must be a small head gasket leak or crack in the block that on;y leaks when hot. F this car

Post by **polskamafia mjl** » 30 Dec 2016, 23:34

broken08 wrote:First $2000 takes it.

$400 and you have a deal.

Post by **erikv11** » 30 Dec 2016, 23:45

broken08 wrote:.... So there must be a small head gasket leak or crack in the block that on;y leaks when hot. F this car

I agree this makes the most sense. This problem would *absolutely* give a positive on the combustion-gases-in-the-coolant test.