98 v70 won't stop overheating!!

[broken08]

I have a 98 v70 turbo awd. I have an upgraded td04-19t turbo, RIP kit, ARD tune, green injectors. That stuff is all good but it runs hot, real hot. Idles around 210-220degrees, but when i drive it, even when I'm being gentle, it will keep rising slowly. I've seen it as high as 250 before I gave up. And I'm talking cruising down the highway at 60 being nice. After a hot run, I'll come back the next morning and low coolant. Top it up and repeat, same result.

I have replaced thermostat, ECT, all the coolant, done a full coolant chemical flush, tested the fan (both speeds, on at 215 and 230) and no improvement. The timing belt was done by the PO about 10k ago, and while I'm not sure the water pump was done, what kind of idiot wouldn't do it at that time? Water shoots out of the radiator as fast as I can hose it in for a flush.

I have a pressure tester. IF I pump all the way to 20 psi it will hold for about 2 hours then gradually (like 12-24 hours) will get down to round 12-15 and just chill there for days. The pressure does not rise from 0 from a cold start to hot, so no massive head leak blowing gasses in to it.

Do I just need to bite the bullet and buy a radiator and do a water pump just to rule them out? I'm losing my mind on this thing and my wife is about to light it one fire (luckily it will burn fast since it can't cool itself)

[erikv11]

If you pull the plugs and inspect them, do they all have a little bit of deposits and soot (i.e. look as expected) or does one or more of them look like it has been steam cleaned? It is possible there is a head gasket problem that only shows up when the engine is hot. Remember head gasket leaks, especially small ones, can easily be only one direction.

Even if a HG problem were to explain the disappearing coolant, it is not obviously a good explanation for the engine running hot. So yeah, maybe there is a clog or poor coolant flow. On the other hand if there is a clog, then where is the coolant going? Could be a pinhole leak somewhere but ehhhh I dunno. Does the coolant bottle have a green cap (good) or a gray one (old design, not good)?

If you decide to go that route, then I would bite the water pump bullet first, it sounds unlikely the radiator is clogged since you have good flow-through with a hose.

Also, the standard interval on the water pump is every other timing belt, and many people let the OEM pump run longer with no ill effects. So for sure it is possible the pump wasn't changed by the PO.

[tryingbe]

Idles around 210-220degrees, but when i drive it, even when I'm being gentle, it will keep rising slowly. I've seen it as high as 250 before I gave up.

A/C on?

Is your radiator cap new?

[scot850]

Check the heater core for leaks. That was where my mysterious coolant leak was.

When was the water pump last changed? I have heard of pumps where the blade became loose so it did not actually turn.

I think the radiator sounds like it is ok, but have you checked it for blockages? May be hard to do, but when it is warm, are there areas of it that are cooler (so no flow/blocked). If you can borrow or have one of those laser type thermometers may be worth seeing if you have areas that are cold spots in the radiator.

Finally, your car could be running too lean and running too hot.

What brand of MAF do you have and has it been changed recently?

Neil.

[paredown]

My "mystery" leak was on the coolant bottle itself, right at the base of the stub-out where the top coolant return line attaches. I did not find it for quite a while, although the system was not pressurizing. (I had done the wp, new OEM thermostat and the timing belt when I got the car; did the heater core about the same time as well.) Heater core is obvious if you smell coolant in the car, or get a weird oily film on the inside of the windows (which I had).

Once I finally found the leak and replaced the coolant bottle, the system pressurized properly, and then it was clear that there was also some leaking on the side seams of the radiator.

Replaced that, and everything is great--it runs one mark higher than before on the gauge, but does not waiver a bit.

[scot850]

Glad you got it sorted. These are 2 other leak areas in these cars once they get to this age.

Neil.

[scot850]

What I should add is have you checked your engine mounts? Particularly the one under the crank pulley, and the upper and lower torque mounts? These can allow the engine to move excessively and cause stress on the radiator and associated pipes, including the coolant header tank.

Neil.