Why do some Pontiacs run hot?

[groucho]

I've had several through the years, and it seems more of these are all over the map in temp than other makes. I have a 60 right now that runs a bit warmer than it should given the conditions, and it has a 7 blade fan and a shroud. I had another 60 a few yrs ago and it wouldn't go past 180 on a 105 degree day in stop and go traffic for 2 hours, and it had a 4 blade and no shroud. Why is it mostly pot luck on Pontiacs more than other makes? Thanks

[nosnerd]

Re: Why do some Pontiacs run hot?


they only run cool in salt water.... ;D

seriously,my buddy had a pontiac yrs ago...and it always ran hot..he eventually got rid of it..too bad it was a nice car..

i was told yrs ago it was core shift (on later stuff)

did you consider the fin count in the rads?just an idea.

[SpiderGearsMan]

Re: Why do some Pontiacs run hot?

rust ,scale and air in the system

[65longroof]

Re: Why do some Pontiacs run hot?

Don't know if the water pump/divider plate setup is the same on a '60 as the mid '60's thru '70's, but there is an issue with the clearance between the impeller and the plate on rebuilt waterpumps. Too much clearance causes it to run warmer.

See link for mod's:

http://www.wallaceracing.com/water-pump-mods.php

[88 Dippy]

Re: Why do some Pontiacs run hot?

not sure on ponchos but some olds run hot becuase of tight clearances most machinest just assume it's like a chevy so they clearances end up being too tight

an olds needs .0035-.003 main clearance. most machine shops think that is way too much and you will have no oil pressure

[starterguy]

Re: Why do some Pontiacs run hot?

My brother currently has the same problem with the 400 in his street rod, new aluminum rad, aluminum wp, electric fan as well as a 7-blade steel one and the motor is fresh (hot tanked and cleaned good) and it refusees to run below 200 right now. Airflow is no problem either as it's in an open roadster ???

[Thumpin455]

Re: Why do some Pontiacs run hot?

Timing can make them run hot, both retarded and advanced. The water pump plate is a big thing, without one it will run hot. Also if it has an aftermarket intake on it, the crossover could be misaligned. I had to open up most of my Edelbrock intakes so the water would flow through it. Moving the oil filter away from the headers helps, as does setting the timing where it runs best, I tend to play around with it a bit, or just get it hot and then advance it until it hard starts, then back it down a bit. After that check to see where it is, and then play with it from there. One of my 455s with 11:1 scr liked 52 degrees total, it had the early closed chamber heads on it.

They also run a bit hotter while they are breaking in, but 200F is not a problem for them. 240 and above is a problem.

[RAIV70Judge]

Re: Why do some Pontiacs run hot?

With my earlier years with Pontiacs I always had the same problem. I can remember a 400 that I had that would run 210 but never lower! Then I met a old timer named Fred. We met at his old (nothing newer than 1974) parts yard. Fred also has a radiator shop. I told him of my Judges ailment with heat, and old Fred told me to change the bushings that go into the timing case cover behind the divider plate. The were not available to the aftermarket until the middle 90s even in a complete gasket kit. If those bushings are loose going into the timing cover, somehow the coolant circulates differently and it forces coolant thru the heater core more than it should, resulting in just enough of a heat issue to be a nuisance but not drastically effect the performance of the engine. Soooooo I found the bushings and I installed them in the 400 that ran the hottest. I didnt change anything else.BAM!!!!! It worked!! I now have the same engine with no other mods in my Judge and it has never been above 185. I can supply part #s if needed.

[455 LeMans]

Re: Why do some Pontiacs run hot?

I had a 400 firebird that ran hot, but my Lemans with a 455 never got above 185. I don't know what was done to the engine, it was rebuit before I bought it.