Thread: Can't shed the heat after going up steep hills? Run a little hot. More capacity? SBC

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Hey guys. I was wondering if anyone could help with this on my rod. All temps are taken via Mech. gauge connected at the heater hose fitting right next to the T-stat.

I think I need more capacity but I really don't want to get a bigger radiator because my car has a custom build radiator 3 pass and it would be very expensive to get another radiator built. I think it holds about 2.5 gallons or so. I am quite sure if I got a 4 pass brass radiator it would do it.

Here is the issue. I can be driving around town w/ stop and go(30 mins or so) in 85 deg. F temps and it stays pretty normal but when I go up a steep hill for about 1 mile or so the temp rises like you would expect going up a hill. About to 207-218 at the intake near the t-stat housing.

After the hill I will be driving around normally and it can't seem to shake the 215 and it might even climb a little to 220 or so. It just won't return to 190 like it did before going up the hill. It just can't get rid of the heat after the hill. Remember these temps are at the intake right by the Tstat (heater hose fitting removed and mech gauge plumbed in) Not sure about the temps at the head. The other day is was 89 Deg F. sunny and after shutting off I did hear the radiator cap let out a little coolant in the overflow tank (non pressurized) and it sucked it back in this morning.

Car runs great. It is a 350 SBC, stock w/ 400 auto trans.. I sometimes run a tstat and sometimes don't. It doesn't matter either way. I have a fan off the water pump that runs all of the time. Have a very large and good fitting fan shroud. All fins are clean on radiator and condenser.
I do notice that my plugs look a little lean so I might richen the mixture. Would that help? I am running almost 100% water right now and corrosion inhibitor. A/C is not on during any of this. I never use it. I put an electric pusher on but it didn't help. I really feel it is a capacty issue. Never uses any coolant etc.


Is there anything I can add that would increase my coolant capacity or anything I can do so it will cool down after the hills? I know a larger radiator will fix it but it is too costly.

Any other ideas? , richening the mixture to a good toasty brown? Retard the timing? Any info would be appreciated.

Yeah, I would fatten up the mixture first. Then I'd be looking at the fan. Is it an 18", 7-blade design steel fan like was used OEM? Are you using a fan clutch? Is the fan turning at least 1.2 times crank speed? Is there sufficient space for hot air to exit the engine compartment?

On the off chance that you're using an Edelbrock, here's the Owner's Manual so you can figure out the tune....
http://www.edelbrock.com/automotive_...ers_manual.pdf

No I am not using a fan clutch. Fan is bolted to the waterpump with a spacer.
I can measure the waterpump pulley diameter and let you know.

The fan is a stock type steel fan. I will check how many blades it has. I remember it saying front on one side of the fan last time it was off.

I don't think I have vacuum advance. I will check. I have HEI but I am not sure on the advance. It will look just like a typical vacuum advance by the distributor like a Ford 302 right?

I had a similar problem a few years ago on my 350 Chevy. Tried more things than I care to admit, to fix it, LOL. Turned out the polished aluminum (read imported crap) water pump had the impeller installed far away from the inside of the water pump casting. It would pump enough water to barely circulate, and fall flat on it face under any load. I installed a FlowCooler "high flow" brand pump and it was fixed. I suspect any "quality pump" would have fixed my problem.

I run a sealed hood and sides (with no louver's) and never even turn my electric fan on, unless it's stop and go traffic. Also pull a trailer with no heating issues. I would agree that nothing is worse than watching that needle climb on the temp gauge.

Good luck chasing it down.

Ok guys thanks for the helpful info. Here is what I found out so far.

Fan is a 7 blade steel fan and the water pump pulley is about 6 inches in diameter.


I checked the timing like you mentioned and it is 35 deg. BTDC (Advance) at idle. I pulled the line off of the vacuum advance and it is vacuum all the time. When I removed the line and plugged it the timing dropped to 5 deg. BTDC.
That being said the car never pings etc. and runs good.

Would the timing cause the running warm problem or not?

In the picture below the top line is the vacuum advance line going to the carb. If I need to change it to not have vacuum all of time does it go on the lower port on the carb? Should I change it to not have vacuum all the time and will this solve the running hot on hills? Will it cool the engine temps?

How will the car run without vacuum on the advance all the time?

I am not sure if it ever had this problem. I bought the car in late fall and the temp was already in the 50s and it needed some brake work. It never ran warm in those temps. I first noticed it when we got an 88 degree day. I want to be able to drive it in the summer temps and not worry. No I haven't changed anything on it besides fixing the brakes.

I used to run a 180 t stat and then I took it out to see if it would make a difference and it runs a little cooler without the t stat but not much at all. Right now it has no t stat.

I know it runs a little lean and I want to richen it up but I am not sure if I will need new jets to do that or if the idle mixtures screws can richen it enough.

Yes I have a picture somewhere of the fan and the shroud. I will post it.

Is a 6 inch water pump pulley ok or is it too big? It sat for about 2 - 3 months before I fixed the brakes.

THanks.

Is there room for a electric fan??.On the other side of things,sometimes it is better to slow down the flow giving the fan a chance to do it's job.There are adapters like Moroso that is like just various holes at the top hose housing to slow down the flow.

Just a thought, but have you checked the temp gage? Is it really overheating or are you taking it for granted because the gage says it is. I'd try a new gage before I'd go swapping water pumps and radiators. Again, just a thought.

You mention that the fins are clean. How does the radiator look inside? Did you do a flush before filling with just water? Trapped air maybe?

If you guys look at the pic, he has a missing carb hold down bolt, good for vacuum leaks, start your engine use an unlit propane torch and hold at the base of the carb if engine speed increases you have vacuum leaks. Its a starting place.

And look at the trans cooler. Is it big enough? Climbing a hill will generate a lot of heat in the trans.

Something that I read a long time ago for SBC was to block the water passage that recirculates hot water in engine. It's the small hole on one side at the bottom of the water pump. I use a small piece of lead. And put the thermostat back in drill a 1/4 inch hole in it first. Doing these things makes sure that all of the water goes through the radiator.
Well thats my 2 cents anyway.
It works well in my car.