454 Running Hot

[micahadams]

84 C30 454/th400

I have been having cooling problems and now I am ready to do almost anything to solve it. I have changed to a new aluminum 3 row rad, 160 stat, then changed to a 160 high flow stat, dual e fans, new water pump, new hoses, flushed the system 3 times, disconnected egr, then re connected it. Straight water, then tried adding water wetter. Not much has helped.

It will idle cool(160), run on the freeway cool, but anytime there is a hill or I am pulling my trailer it will climb to 210+.

I was talking to a guy today who said Chevy in the 80's needed to conform to smog laws and to get the motors to pass needed to retard the cam timing -9 degrees. I have also heard that 80's heads have small water ports.

Here is my question. Has anyone has a cooling problem and found a way to fix it? I am thinking maybe a cam change will help, or a adjustable cam gears. I haved owned several small blocks that ran fine. This problem seems to happen to a lot of BBC's

[VileZambonie]

Do you have a spring in the lower radiator hose? Do you have the belt routed correctly? Is it actually overheating or are you just seeing your gauge rise?

[Maintenanceman]

these trucks are just so hot anyway they naturally run hot lol

[choptop]

Does you truck have cats on it and is it possible that they could be stopping up. I have never seen 200 on any of my bigblock trucks when pulling, so I was curious if maybe your exhaust is restricted.

[micahadams]

Yea I have the spring in the lower hose. No cats. Thorley tri y's with x pipe and flowmasters. Timing is 36 degrees total. In the summer w/ the A/C on or off I can get it to boil over.

It has to be something to do with all the smog stuff. I just dont get how new cars these days have radiators the size of school books and they run perfect, but I have a monster of a radiator and it still runs hot. I think I am going to try to change the cam and intake and see what happens.

Any other thoughts?

Choptop, tell me more about your motor.

[Lt.Del]

coptop may be on to something.  I know in my 79,  years ago, it would overheat without any apparent reason.  I found out the cat was clogged with junk and restricted the exhaust flow, which backed up the pressure and caused the engine to overheat big time.

It should not overheat just because of smog stuff unless you have real problem. 

You can have reverse rotation water pumps, bad t-stadt (even though it's new), clogged radiator paths, timing is off, bad exhaust flow, etc...

[Da67goatman]

Does the radiator also cool the trans fluid on your? If so the trans runs ALOT hotter than the engine.  I had an overheating issue once when i got my 2wd almost stuck in the snow.  By shifting from forward to reverse so many times and not having adequate airflow the tranny heated up and transferred the heat through the radiator to the coolant causing the engine to overheat.  Might be worth looking into.  Check your tanny fluid level and smell it to find out if its burnt.  If it smells burnt The problem would be caused by the tranny.  Just a suggestion.

[micahadams]

I have checked the t stat by boiling it, if opens fine. Radiator is brand new. I even drained the bottom drains on the block incase there was any crud in there. The trand fluid runs into the rad 1st, then into a aux cooler. Fluid looks and smells fine.

Part of the problem is a 454 that only put out 245 hp. The throttle is open pretty far just to get the truck moving with a trailer.

I check the a/f with a wideband o2 and it never runs lean either.

[VileZambonie]

Run it with a spill free funnel on it and see if you are getting any bubbles.... If you're positive everything is correct and it's still overheating you probably have a head gasket on it's way out or some seriously clogged coolant jackets. Don't blame your cam

[micahadams]

 The only reason I blame the cam and its timing is because my parents in 1986 bought a Deluxe 20 with the same motor trans combo 454/400 and it would overheat on them all the time. They owned the truck up until a few years ago and always had problems with it. They added a custom made huge radiator, ran the stock clutch fan with aux e fan pusher. It only has a temp warning light so no way to tell if its running hot till its too late but while towing the light would come on.

A friend on mine also had a mid 80's Chevy dually and it would over heat. I remember someone saying that in the 80's the ford 460 needed to be ran at 6 degrees BEFORE tdc to pass smog.

I dont think its the head gasket because there is no water in the oil and vice versa, and it only happens when pulling a long hill. Its not like the cylinder pressure is pressurizing the cooling system, as for as I know.

[Josh454]

Is the fan shroud intact?  Is it the correct fan and clutch for the truck?

[Jim Rockford]

Correct fan shroud and a 180-195 t stat. betting the 160 isn't leaving the water in the radiator long enough to cool off.

[micahadams]

I have dual electric fans now that pull 2600 cfm. But with the old setup I did have the correct shroud and fan.

I though about the higher temp t stat but am not convinced it will solve my problem.

[VileZambonie]

It won't fix your problem unless you have a faulty t-stat now. The polarity of your fans is correct right? Did you have this problem with the fan shroud and clutch fan? If a head gasket is leaking it doesn't mean you will mix coolant with oil.

[micahadams]

Yea i am just trying to think of everything. Yes fans are wire correct. They are on an adjustable thermostat. What I did to test them is turn up the adjustable knob till the truck got to about 200 degrees at idle, then turned the knob till they turned on. It cooled the water down fast, but thats at idle when the motor isnt making much heat. With the stock fan and shroud it ran hot too. The e fans helped, it just seems like when putting a load on the motor nothing will cool it.

I was joking with my buddy about putting my old radiator in the bed of the truck and using the dischage line of the heater core to circ the water from the "bed" radiator to the main raidator. I know if doesnt really help the cooling of the system with removing heat, but it would add cooler water for a certain amount of time.