Thread: Hot Running Engine

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I have a 305, an autozone reman with about 15k on it.
It was in an 84 camaro (with all the 84 emmissions crap) and it wold run hot - as in boil over once parked after 30-409 minutes of driving (even hiway cruising).

I had the rad checked for HC (leaking head gasket) and no problems found.

Put the engine into a Jeep - taking out a 78 or so 305. replaced the 84 parts with the 78 305 parts: carb, dist, water pump, new temp sensor for guage, new 180 thermostat. Kept the 'jeep' fan, rad, shroud, exh manifolds. I didn't check the pump - it don't leak and the pulley turns. no idea if it pumps though.

When i got the jeep the 305 had a broken rod. The PO said it ran fine until then (no overheating) so I assume then the cooling system is OK. (rad, pump, fan/shroud combo)

I set the timing to max vac at idle..pinged when at p temp up a hill so ihave backed it off. I will be re0checking thte TV cable as well and after it cools go for another ride.

Since the motor ran hot in teh last car and this one, i assume the motor is the issue...any ideas on what is the cause or what to try to cure it? A bigger rad is not my first choice cost wise, but it has just a 2 core in it now (the camaro had AC (broken) and only had a 2 core in it)

Should i just change the water pump for the heck of it? i have the old camaro pump...i can check it - i doubt BOTH pumps would not pump. I left the cap off to bleed...never did see the flow i was expecting BUT i may not have let it get hot enough fot the thermostat to open..will check for flow at lunch.

Any thoughts?

no..the rad is very much higher than anything else - in the jeep.
i can try that...

the old camaro pump seems fine...i can try no thermostat and see what that does (flow and temp wise.) I remeber having an old ford that i left teh t-stat out of and other than having no heat cause it never got hot enough i don't recall any major issues. (gas mileage or emmissions may have suffered...who cared then and now, well, no emmissions on it and mileage will suck anyway

pulled the t stat out - it be flowing now!
the t-stat looks 'normal'. did a bit of web research and found remarks regarding 'balanced flow' t-stats...i have one for the 350 build we are doing..different looking critter. If the no-t-stat bit works i'll try the balanced flow one and see what results it gives.

since i have to road test it anyway, might as well cruise on over to Jerry's Curb Service, it being friday night and all...

No t-stat and things are better (take longer to get too hot, cools off quicker) but still overheats....

I am getting desperate maybe...tempted to pull the heads and check the cooling passages for blockage.

Any ideas that would make an engine run too hot (as opposed to a cooling system that doesn't dissipate enough heat)?

hiway speeds are not good, temp wise, nor are long hills...just jumpin on it for amile or 2 seems to have no effect....i would expect hiway cruising to drop teh temp fairly rapidly - but it goes UP?

HELP!

Tstat out, different cooling systems. Still overheating, I would check for a head gasket, or warped heads or block. If not them then I would replace the pump(if you haven't done that already. If not those, what about a blocked water port?
My Tbird was overheating like crazy, no oil in water and no water in oil but the head gasket was shot and warped the heads. Didn't figure that out til it was too late for the heads. I had just thought it was a bad guage for a while then, til it over heated enough to shut down. Well the guage was bad, was reading lower than it actually was.
But take a look into the things I mentioned. Hopefully its something simple.

is your rad a 2 core or 4 core? if its a 2 then try going to a 4. how big is the fan your running? can you go bigger like more blades? if your running electrick then try going with a lower temp when it turns on. maybe this well help you out..

Cd

Originally posted by joker51
Tstat out, different cooling systems. Still overheating, I would check for a head gasket, or warped heads or block. If not them then I would replace the pump(if you haven't done that already. If not those, what about a blocked water port?
My Tbird was overheating like crazy, no oil in water and no water in oil but the head gasket was shot and warped the heads. Didn't figure that out til it was too late for the heads. I had just thought it was a bad guage for a while then, til it over heated enough to shut down. Well the guage was bad, was reading lower than it actually was.
But take a look into the things I mentioned. Hopefully its something simple.

yeah, i figure i have to tear it apart. sucks, as i just put it in last week, so it would have been easier on the stand. oh well.
i have another set of heads - have to chekc them as they are on the old motor that broke a rod, so i don't know if any valve damage occurred when things seperted. want to look inside anyway...just no time yet. maybe today - it's raining.

I think i have it fixed - Oh it's soooo good to be smart!

What was it? For $5 i'll tell ya...

It was...drumroll please - mis adjusted valves!

it occurred to me that too tight valves might cause an over heat condition - and when the revs go up and oil pressure goes up and combustion pressures go up you get too much heat in all the wrong places. As to how they got too tight, well that is another mystery.

So for the few minutes it takes to pull a valve cover and check I figure'd i'd try it....idle engine, loosen till it clacks, tighten 1/4 turn more when the clack stops. Well, on the left bank EVERY valve was too tight, some by 3 turns! Idles smoother now too. on the right side only 1 seemed to be out of adjustment.

So i go for a ride - can't get teh guage to read above 210, and more importantly, when cruising at about 40mph with the guage at 210 it actually starts to drop! That is real progress!

My wife is out now for a hi way test...a real road test. I'll know soon if it was successful, and then i can put the thermostat back in. Got a good deal more power from the engine too.

Next obstacle may be gas mileage...got about 9 mpg on the first 60 miles....not good, not good at all.

Good work Screamer, that didn't even occur to me to look at that.

Jeep is a 305, miled, with a 700R4 and 3.08 gears....

mileage is WAY up and temps are staying down. Got the B&M megashifter adjusted correclty now - the PO was a know-nothing! Now I have PARK and 1st, and the detents all line up. This gotta help mileage and heat too.

Progress on a project - what a wonderful feeling!

Good job man. Overdrive-isnt it great?