327 overheating at idle

[Joseph P.]

I have a 65, 327, 300hp that is overheating at idle. I have put a new clutch fan on. I have read alot of info for the BB's but not the SB's. Can anyone shed some light on where to start. I sprayed water through the front of the car into the radiator when it was at about 220 degrees. The temp dropped to 180 within a minute or so. I was told that this meant the radiator was bad. In the articles I read it mentioned timing and vacuum, etc. and I don't know if this is also relevant for the 327's and if so what setting should I have and what vac should I use? Thank you in advance for your input. It is greatly appreciated. Joe

[Clem Z.]

Re: 327 overheating at idle

I have a 65, 327, 300hp that is overheating at idle. I have put a new clutch fan on. I have read alot of info for the BB's but not the SB's. Can anyone shed some light on where to start. I sprayed water through the front of the car into the radiator when it was at about 220 degrees. The temp dropped to 180 within a minute or so. I was told that this meant the radiator was bad. In the articles I read it mentioned timing and vacuum, etc. and I don't know if this is also relevant for the 327's and if so what setting should I have and what vac should I use? Thank you in advance for your input. It is greatly appreciated. Joe

the fins can loose contact with the tubes and lose the heat transfer on older rads. see if the fins are still tight between the tubes.

[Timothy B.]

Re: 327 overheating at idle

Joseph,

I agree with Clem, usually it's a radiator issue. Also, the timing can cause overheat problems, if you have the inital timing set at 6-10*BTDC and the vacuum advance is working properly timing should not be a issue. It may be wise at some point to remove the distributor and clean/ lube and verify everything is in spec.

Keep all parts at stock spec (fan, fan clutch, water pump etc.) and find the real cause for the warm engine temperature. Don't fall for these $$ hot rod fixes. If you have 50/50 antifreeze and water, a good radiator cap that holds 13lbs. pressure, 220* will not hurt that engine.

You should be able to feel a noticable temperature difference when the engine is hot between the (hot) top radiator hose and the cooler (lower) radiator hose.

Don't forget about the temperature guage/sender issues many have reported, read in the archives about this because this may help with your car.

[Joe R.]

Re: 327 overheating at idle

I have a 65, 327, 300hp that is overheating at idle. I have put a new clutch fan on. I have read alot of info for the BB's but not the SB's. Can anyone shed some light on where to start. I sprayed water through the front of the car into the radiator when it was at about 220 degrees. The temp dropped to 180 within a minute or so. I was told that this meant the radiator was bad. In the articles I read it mentioned timing and vacuum, etc. and I don't know if this is also relevant for the 327's and if so what setting should I have and what vac should I use? Thank you in advance for your input. It is greatly appreciated. Joe

Joe,

Are you certain that it is really 220 degrees? In other words, I'd recommend getting one of them fancy IR temperature guns to verify the measurement.

Joe

[Mark G.]

Re: 327 overheating at idle

Joe -

This may shed some light on the issue; TSB DR#774, 11-23-65. The calibration is suspect and a replacement is suggested.

Mark

[Clem Z.]

Re: 327 overheating at idle

Joe -

This may shed some light on the issue; TSB DR#774, 11-23-65. The calibration is suspect and a replacement is suggested.

Mark

if you are not puking water out the over flow i would not worry

[Duke W.]

Re: 327 overheating at idle

The same issues and checks apply to overheating on SBs as on BBs. BBs have more tendency to overheat since they have less cooling system margin.

Radiator? shroud? VAC correct and functional? IIRC the '65 300 HP has that one year only oddball ...437 VAC. The best replacement is a B22 if it's a manual trans and B20 or B26 if a Powerglide.

If everything is to OE spec and functioning properly SBs should rarely run high coolant temp.

See the companion threat on BB overheating and run the same recommended checks.

Duke

[Clem Z.]

Re: 327 overheating at idle

on a BBC make sure the foam piece is on top of the core support that seals to the hood when closed. also insert a restrictor in the water pump to intake manifold bypass hose with 1/4" hole in it as this will force more water thru the rad.

[Joseph P.]

Re: 327 overheating at idle

I can't thank you guys enough for the pics and the great info. I will start to go down the list. First an IR and then I need to take a look at the distributor and clean it up. thanks again. Joe

[Joseph P.]

Re: 327 overheating at idle

I read all the posts (thanks to all) and followed them carefully I changed out the radiator to a Dewitts aluminum. It had a cooper one in it. I set the dwell, timing etc. The timing chain seems to have stretched because I could not set at 8 degrees, it ran terrible. I added new 50/50 and it is still running hot. I bought an IR gun and the gauge and the actual temp on the IR gun are the same. I did not change the fan clutch. Could that cause the problem? I don't know what else to do. Need some input at this stage. Joe

[Jim T.]

Re: 327 overheating at idle

How did you verify that your vacuum advance installed in the distributor was working properly?

[Gerard F.]

Re: 327 overheating at idle

I read all the posts (thanks to all) and followed them carefully I changed out the radiator to a Dewitts aluminum. It had a cooper one in it. I set the dwell, timing etc. The timing chain seems to have stretched because I could not set at 8 degrees, it ran terrible. I added new 50/50 and it is still running hot. I bought an IR gun and the gauge and the actual temp on the IR gun are the same. I did not change the fan clutch. Could that cause the problem? I don't know what else to do. Need some input at this stage. Joe

Joe,

Looks like you are doing everything right with a new aluminum radiator , new fan clutch, checking the timing and vacuum advance. Next thing to check is the water pump and thermostat valve. Maybe go to one of those high flow ones.

I went through all of your problems on my 67 with my original radiator. Finally reversed flushed out the radiator (gently) and engine block, got a new repro fan clutch and a refurbed correct water pump, timing and advance set to factory, problem was solved.

No IR gun, just taped a meat thermometer to the engine outlet to check the temp gage. It was right on.

[Timothy B.]

Re: 327 overheating at idle

Joseph,

If you could not time the car properly something is not correct, 8* BTDC at idle should not be a problem.

Be sure the vacuume advance is not connected when setting initial timing with timing light. After setting initial timing plug the advance control in and check that it's also advancing at idle.

[James G.]

Re: 327 overheating at idle

Hey Joe, if you removed the distributor you might be off a tooth or two which might affect timing.

[Jim V.]

Re: 327 overheating at idle

Been there done that...suffered through a similar costly experience....

First if you haven't already...get a system pressure tester from Autozone to insure you have NO system leaks.... takes 5 mins to test. I found a leak at the suction side (lower) hose causing pump cavatation.

Second check out potential vacuum leaks....see this thread.


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