Low engine temps

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70DusterNM

70DusterNM

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Ok guys Im really stumped on this one.. So me and my dad built a "lowly" 318 over the summer and its in the car now and runs but the only problem with it is the low engine temp. The engine has no leaks and the thermo isnt stuck on open so I dont know what else could be causing the problem. It should run around 190-200 but instead maxes out at around 160. any ideas?
-Nick
 
What thermostat you running? Also are you using a 50/50 mix of antifreeze? My guess is the thermostat your using is the 160
 
If the thermostat is a 195F type, I would try another sending unit, or another gauge set-up entirely. If you have access to a laser temp gun, you can check the temp at the water outlet. That should tell you where you're at temp-wise.
 
The thermostat is a 195, thought maybe it was stuck open so replaced it. Running a 50/50 mix on the antifreeze. The engine specs are a 318, stock bore, 5.2 magnum heads, comp 256 cam, air gap manifold and holley 4160 carb. The radiator is a 26" from I think an 87 Diplomat with a 7 blade fan on a viscous clutch with a shroud. Timing is set to about 8 degrees at around 900 RPM, but I don't know the total timing and when it's all in.

The aftermarket guage, a cheap Equus electrical sender reads 160-160 whether stop and go traffic or highway driving. The factory gauge runs between a third and a half, and the air coming out of the heater core is lukewarm at best, by no means as warm as it should be.

Hope this additional info helps, any and all ideas and suggestions are appreciated.
 
Go borrow a mech. Temp gauge and really check the thing. Also if what Water pump are you using? (I mean nothing against you here ok, but you are the only guy I've seen that as a problem of the temp not coming up. Everybody else if fighting the temps and trying to lower them because we beat the piss out of them, trying to make them go faster).
 
New 7 blade water pump I believe, I'll have to double check. It's the AC version for the 318. I do see flow across the top of the radiator when it's warmed up.

Yep, I know, I am surprised as well that it's running cold instead of running hot, and when the son is back over spring break we'll get a different gauge and a laser thermometer to double check the temps. I do know that the radiator hoses don't feel nearly as hot as I remember previous 318's I've had being.

Other than freezing while driving it is fun to drive around.
 
maybe the fan is locking solid. does it get hotter at idle? (i am at a loss & just throwin stuff out there off the top of my head). Late M-body radiators are very efficient, you've got a 7-blade viscous fan, an AC style waterpump AND a shroud. All this stuff is very efficient at transfering heat. On a relatively mild 318 and heads that are noted to not need much timing [fast burn], all this equals a cool running engine (yes, that are known for running cool) {remind me to copy your exact set up when I set up my A body with the stroker motor and roller cam.} One thing that you must remember is that even if you replace a suspect part with a new one, it does not mean that the new one is good either. Especially with something like a thermostat (the quality seems to be going down on these things). You may need to try the old "putting the thermostat in a pot of water on the stove with thermometer trick" to check and see where the thing is actually opening. (sorry for long post)
 
I agree with checking your gauge against a known quantity.
You could also carefully block off the rad a little at a time to see if it increases the temp.
 
Depending on what your weather is, when I was driving these cars year round I'd have to block 1/2 the radiator off with cardboard to get it to operating temp when it got really cold. Yesterday morning was -10° at my house, today was a balmy 5°. If your temps are cold, you may need to limit the airflow thru the radiator to get it hotter. Think like the heavy trucks with the grille covers...
 
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