cooling question

[cbarr300]

Ok, here's the scoop: (cliffs at bottom)

The car runs at 185* while cruising around town.

Once I get to, say, a parking lot and look for a place to park, the temps will climb up to about 210* or 220*.

Once I'm at a dead stop the temps will start creeping back down.

If I'm staying at idle and I rev the engine up I can see (instantly) the temp drop a couple degrees.

Here's the thing that stumps me: If I'm take off from a stop the temps will shoot up 4-5 degrees and then come back down once I'm cruising around...but if I'm going a steady speed and get on it the temps usually drop a degree until I come back to a cruise where they rise back up to 185*.

My high-speed is turning on and I do have pressure on the upper radiator hose. I did a coolant system pressure test and it held the pressure.

There's only two things I could think it would be. Either my waterpump is on it's way out....and the reason it cools when I rev it is because the blades are pumping more water through.

orrrr, I have a bad headgasket and combustion gasses are getting into the coolant when I'm taking off and since I have a fluidyne it can handle (somewhat) the extra heat. There's no signs of a blown headgasket though. The engine doesn't have a miss and there's no oil in coolant or vice-versa. I'm gonna do a compression test once I get the time.

I'm gonna try and hook it up to a sniffer, too

Any ideas....I'm stumped.

Cliff: getting warm on take-off. Pressure in upper hose. both fan speeds are working when they should. cools down if I rev it at an idle. No signs of blown headgasket (will do comp. test later on)

 

[TrueBlue95GT]

If I had to guess, I'd say waterpump....but if you change it, I'd also replace the thermostat and radiator cap while I was at it...

 

[Stanger007]

Are you running stock fan temps in the EEC? Stock settings IIRC are around 210-220 for the high/low fans.

Wes

 

[cbarr300]

I'm running modified fan settings.

I checked my compression and one cylinder has 30 and the other one next to it (the one someone dropped a washer in), had 120...the rest had 145-150. Also, I drove it for a while today and noticed coolant level was getting lower.

It's funny though, it's not putting out any white smoke and I can tell it's a LITTLE down on power...but it pulls nice and strong. Guess it went in just the right place.

I didn't have any detonation or any overheating....gasket was installed properly....go fig

I'm pretty close to getting my new long block and other than the coolant level dropping and the weird temp thing I never would have noticed a blown headgasket...btw, it never overheats...just gets warm (220 which is hot by my, and most other people's standards).

ah well

 

[Dino Dino Bambino]

It sounds to me that your coolant temps. are behaving normally except that you almost certainly have a blown head gasket. You'll probably find the spark plug on the low compression cylinder is either wet or stained brown by coolant.
I recently had the same problem and found the head gasket was blown between the water jacket and the combustion chamber of cylinder no.1, so of course there was no mixing of oil and coolant; just the odd puff of white smoke from the passenger side tailpipe at idle. I used the opportunity to home port the heads and lower intake while they were off, and the heads were milled 0.010" resulting in a 0.14:1 compression ratio increase.

 

[cbarr300]

yeah, I think a new longblock would fix it. nothing major though, before I was wanting a 351 based beast....but I think I'd be perfectly happy with slapping my s-trim on a 331 with some somewhat mild heads.

 

[baglock1]

What are you using to measure the temps? Hopefully a quality aftermarket gauge?

 

[cbarr300]

of course, the stock one's crap

I'm running the autometer cobalt full sweep. I'm gonna tear into it tonight maybe and change the headgasket out