91 VR4 overheating issue... kooky ...

[box]

Off the top of my head, low fan speed should only make the one large radiator fan go, high speed should make both fans go (and make the large fan run at high speed).

You've done well so far though. Time to pull the water pump out and have a nosey so you can rule it out. I've never seen it personally, but I have heard of impellers falling off the shaft on cheap pumps.

When you say it overheats "quickly" when you drive it, how "quickly" does it overheat?

[dudewith91vr4]

Off the top of my head, low fan speed should only make the one large radiator fan go, high speed should make both fans go (and make the large fan run at high speed).

You've done well so far though. Time to pull the water pump out and have a nosey so you can rule it out. I've never seen it personally, but I have heard of impellers falling off the shaft on cheap pumps.

When you say it overheats "quickly" when you drive it, how "quickly" does it overheat?

if it's at operating temp when i drive it, it'll take under a minute or two to overheat. i don't see water in the oil, and when i let the engine cool and take off the filler cap, i can see coolant. how do i eliminate the possibility of a blown head gasket? it doesn't emit white smoke, except for what looks like condensation ... someone mentioned o-rings attached to some pipe that runs through the manifold, can that be a possibility?

also, i didn't think it really applied here, until after i read up on the intercoolers... the engine did start to make knocking sounds (like valve ticking or bad plugs).. it started shortly before the overheating issues started... would a bad knock sensor cause overheating, because i do see some moisture on that sensor, beneath the plenum...

[sergechronos]

Pull the water neck off and see if there's water in the valley, or pull that water crossover pipe out and check the o rings. If you have any leaks, the system isn't pressurized and will boil and cause overheating pretty quickly. I had a small leak on a TB hose that caused overheating while driving. Ended up having to cut the hose to the TB and loop it to get back home.

[donniekak]

Do a coolant system pressure test, and check the cooling system for hydrocarbons.

[box]

when i let the engine cool and take off the filler cap, i can see coolant

Is it full right to the top of the filler neck or is the water level quite low?

Your knock sensor is leaking and should be replaced like I told you on page 1, but it won't be causing these problems so don't worry about it for now.

Now is that 1-2 minutes of hard driving, on boost? Or 1-2 minutes of cruising?

[dudewith91vr4]

once it reaches operating temp, 1 or 2 minutes of cruising will overheat it ... then if you let it idle, it'll come back down to the midway mark of the temp gauge

[box]

And what's the coolant level like?

[dudewith91vr4]

coolant is up to the bottom of the filler neck...

happy holidays, everyone

[dudewith91vr4]

it there a shortcut for removing the crossover pipe, is it possible to pull it out through the thermostat housing side?

[CoopKill]

I believe you have to remove it from that side anyway.