Engine Temperature

[synack]

I overheated my 22ZX w/ a 454 Mag the other day and I think I tracked it down to what I think was a stuck thermostat. I replaced the thermostat with another 160 degree thermostat and was doing some testing yesterday to make sure everything was in order.

Ever since the overheat, I'm keeping more of an eye on the temp guage and I think it's behaving a little differently than before. Previously, the temp would hover around 160... now it sits around 170. When I'm revving high (3000-4000 RPM), it goes as high as 190. I didn't get to do an extended high speed run to see if it would go higher. If I slow down, then the temp drops back down to 170ish.

Also, the temperature around here has been in the 90s for the past week or so, so the water temp is probably the warmest its been all year. That could have contributed somewhat to a change in temp of the engine.

So, with that all said, I can assume that the impeller is good since the temp drops immediately at low RPM. The thermostat is now new and should be in good working order. The engine water pump is probably ok...but how can you tell when it goes bad? Do they weep like car ones? Am I just getting over concerned about nothing? ;-)

[txtaz]

synack,
The circ water pumps have a weep hole on the top front.
As far as your temp, It sounds ok to me. I run at 180F and bumps up to 190 after a high speed run and slowing down, then back to 180. When you said "revving", I hope you mean underway. I have heard that it is not good to rev an engine that high in idle for long.
Also, there is a variance in thermostats. One may open at 160 and another at 170. If you are concerned, go get another one and try it.
Hope this helps.
Wes

[synack]

Yes, the revving I was talking about was in motion.

That's good to know about the temps. I bet that the thermostat that i had before was flakey or just opened up sooner. Now with the new thermostat, it behaves better or more properly.

Thanks for putting my mind at ease! ;-)

[Trueser]

Rob,
Thats the one thing we were going to replace and forgot. I'm sure its running fine, When you going to order pro charger? Before Texas....


Mike

[synack]

Tested the crap outta the boat today. It ran like a champ! Steady at 170 then would run up to 180-190 at speed and then back down at a rest.

[RedDog]

I can assume that the impeller is good since the temp drops immediately at low RPM.

I have heard that IS a sign of a worn impeller..

My 502 MAG never goes above 150 - 155 F

[Reedy]

How old is your impeller? I was told they should be replaced every two to three years depending on use?

I have heard that IS a sign of a worn impeller..

My 502 MAG never goes above 150 - 155 F

[sweet 16 1966]

Sounds like the 502 mag has no thermostat with that low temp?

[Trueser]

New housing and impeller installed in the spring.

And its a 454 big block...

[MOP]

There is a standard test out of the manual to check the pumps flow disconnect the pumps outlet hose and put it in a 1 gallon container, start the engine at idle it should fill the container in about 35-40 seconds. You must do this test with the pump sucking its own water not on a flushette!
A fact demonstrated to our class in tech school is rubber impeller pumps have flow positive at low speeds but a high speed the blades stay bent back away from the housing they act more like a centrifugal pump. So far none of the temps seem to high especially in warm water, another point we are all looking at analog gauges which are close but no cigar. A temp gun or melt sticks are the only real accurate way to check temp.

Phil

[NeedSpeed]

Couple of things to consider:

-Impellers are cheap (<$20), might want to change to set your mind at ease.
-Perhaps the water temp sender is faulty.
-Check timing.
-Pull plugs to get a read. White plugs means it's running hot.

I wouldn't worry about the temp unless you start getting over 210 degrees on that engine. My 502 MAG runs about 190 consistently under load.