C30 7.4 454 running hot

[REIDicoulous]

I have a 82 c30 Scottsdale camper special with a 454 I have replaced the entire cooling system new radiator, new severe duty water pump, severe duty fan clutch, new hoses, new 180 thermostat. I have pulled the plugs out of the engine and looked inside with a bore scope nothing looks plugged up, checked the timing and carb everything looks good but the engine still runs 210 and Starts creeping up even more running down the road. I have checked to see if the gauge is correct and it's spot on. I am out of things to check. Any ideas?
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[mrolds88]

Double check the tstat. Had one years ago, brand new out of the box that was bad. cost me a crank on a 455 Olds. Pull it, put it in a pan of water along with a thermometer and see when it opens. Oh and one other thing, check the a/c condensor and any coolers that may be there too!!

[REIDicoulous]

I have checked the t stat and even bought the high flow one from oreillys with the same results, I washed the condenser out when I replaced the radiator.
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[meatwagon83]

mine runs 210 no matter what i do, same truck as yours just a year newer, and mines a dually

[aficio]

does it still have a fan shroud?

[Rufton]

Check radiator inlet and outlet temp w/ IR gun.
Do you know if engine is sludge free?
Are right and left heads the same temp?

[jon75]

This might sound silly but did you replace the radiator cap? Those do go bad, even if they look perfect. They are cheap enough that you should have a new one on there regardless.

If that's not the problem, sometimes ignition timing can cause an engine to run warmer than necessary. If the timing is too far advanced, heat can build up in the heads and cause things to warm up.

[JellyBeanDriver]

I'm interested in hearing your outcome. Similar situation here. I think some of the reason is the temp sensor being in the head instead of the water outlet or intake manifold in the water outlet path like most other cars.

Why did you replace all the bits to begin with? Did you have this problem before the changeout? Is the radiator 'the same'? (4-core)

Ours overheats towing the horse trailer, up a grade. Going to ditch the 4-core brass and put in a plastic tanked 2 core HD unit to see if that makes a difference (I think our 4-core is not well built or engineered).

Originally Posted by jon75

If the timing is too far advanced, heat can build up in the heads and cause things to warm up.

Not questioning you, but I've read conflicting data on this. So many people ask if the timing is retarded. Getting hotter when advanced makes sense to me, retarded not but that's what most people say.

[jon75]

Could be head gaskets too.

[BigBlocksRule]

We built a stroker for my son using Pro Topline heads. We worried a lot about it because it shows to be running hot. Finally figured out that the heads are a lot thicker than stockers and retain heat a lot worse. His shows about 200* and has run at that for about 40,000 miles with no problem. We finally shot the radiator with an infrared gun and found it's running about the same temp as mine with a 350 that shows 175* on the gauge. Even after a long haul, this thing doesn't sound or act hot when turned off, no tic-tic-tic as it cools down, no excess coolant running into the overflow.

[Rufton]

Originally Posted by REIDicoulous

the engine still runs 210 and Starts creeping up even more running down the road.

I consider head temp normal between 200 to 215F on my small blocks.
How much does it creep up?

[REIDicoulous]

I replaced the radiator because it was the original and started to leak and slughtly pluged ,couldn't be repaired, so I went ahead and replaced the water pump, hoses, cap, tstat, clutch, since they were all still original and didn't want to have any problems, it still has the fan shroud. It was starting to get hot before I swapped everything. All the new parts have helped but not fixed the problem. I will check all the temps with an ir gun this afternoon.
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[Robert1970C20rstbukt]

Are you having to add coolant to the radiator often? My '84 454 welding truck runs about 195 degrees with the A/C running. I have a 14" Hayden booster fan in front of the condenser so that helps a lot at slow speeds.

[RT Big Block]

Have you check the lower radiator hose ? It might be sucking itself shut. The wire goes bad in them sometimes .

[JellyBeanDriver]

Originally Posted by RT Big Block

Have you check the lower radiator hose ? It might be sucking itself shut. The wire goes bad in them sometimes .

I have not seen wire in the lower radiator hose for 30 years. Read something about them not being needed except at the factory when they would pull a vacuum before filling a system with coolant just to prevent air pockets. After this they're not needed.

[tucsonjwt]

I have had 2 454 C20 squares and neither ran hot, except when the water pump blew. My current 83 has a 160 degree thermostat and it runs at just under 160 degrees according to the temp gauge, although that could be off. I am going to install an auxillary A/C condensor fan to help with 134a A/C refrigerant, so it will probably run even cooler.