qdude79

Fresh (10k) motor, all new cooling parts. I have a very slight leak at the drain plug (might leave a drip on the ground after parking).

I cool GREAT at idle. At higher rpms or inclines, it heats up. Pull over and idle, two minutes later it's cooled down.

Question: can that tiny drip be enough to de-pressurize the system to overheat under load? If so, wouldn't it do the same at idle?

I have to think that there's something strange happening here, 'cause the cooling system seems to be wonderfully efficient when not under load.

Thoughts?

Keith B.

First suspect when no cool under load is the [clogged]radiator. Second is some other path in the coolant flow that's blocked(unlikely, but possible). Third is fan clutch(rare). You didn't switch type of coolant recently, did you?

qdude79

Brand new radiator, e-fan (16" Summit), no change in coolant. Hoses brand new, etc. Darn thing is giving me fits.

toyota4x4907

Hows the T-stat?

Dirt Driver

I would say if it's never boiling, then the leak isn't the cause.

Lower hose collapsing at rpms above idle, perhaps?

qdude79

New stat at rebuild (stock temp), lower hose new, but how would I test it? No boiling, either.

Dirt Driver

Raise the rpm while looking at the hose.

mick cassidy

well my thoughts on this are if sludge caused a plug in a drain plug you got sludge in other areas minerals in the water DO CAUSE CORROSION im saving to upgrade to a alum radiator ...... the copper brass rads really dont last that long UNLESS you flush and change your coolant every 6-9 mos

Dirt Driver

Maybe if you use chlorinated and mineral-laden hose water you're talking about.

qdude79

No sludge, whole system's practically new. Lousy drain plug had a drip since installed. Nothing but distilled used from the get go.

I have to wonder if it's truly a cooling problem or a lean fuel mix problem...

Is there enough "play/flexibility" in the stock ECU to compensate enough fuel for the upgrades I've done, maybe??

I know there are other more "built" 22RE's out there, but the heat here is extreme. Already hit 112 this year...

Dirt Driver

Wait, is this with the stock idiot gage? It's little better than an idiot light...

Does it get hot if you run the rpm up in neutral for a while?

qdude79

Yes, it is with the stock gauge, and I haven't tried revving it in neutral. Will try today...

Marc

Drip probably won't cause the overheat. If it dripped enough to allow a loss in pressure (and I bet it doesn't) it would just lower the boiling point of the coolant.

Gotta ask this - is your electric fan turning the right way?
If it's behind the rad it should be pulling.

Try a manual gauge or temp gun at the outlet.

qdude79

I should have clarified: it is a puller, it is turning the right way. Comes on at the appropriate time.

Thought about the accuracy of the stock gauge, but even if "hot" on the gauge isn't that hot, it's still a fair deal above normal and I'd like to see it stay steady. Will try to get a reading on actual temp if I can get an infrared thermometer.

Sidenote: Just replaced 20 year old fuel pump for preventative reasons, and in case it was tired and not pushing hard enough (causing lean situation). Also wanted to see inside the tank. Result: pump was fine, though I replaced it and the screen. Tank was clean as could be. No major sediment. On to the next suspect...

qdude79

No collapsing hose, even tried backing the timing off a bit. No luck. I still have to wonder, with the 268 cam and an opened intake and exhaust if I'm not running too lean...