Car heats up going up a slight grade - help...

Ok GRMrs, what am I missing?

Car runs pretty good (still tinkering with jetting...), and when not running up a grade, runs fairly cool.

2.0 M10, 284 cam, 9.5:1, Weber 32/36 (idle 70/60, mains 150/165, Airs 145/175 - I think the primary main is a bit too rich...), header, stock cooling system. Oil is full up, as is radiator.

There is a weensie little leak at the water pump/timing cover (apparently I missed a spot with the gasket sealer...), but it's literally only a couple drops at a time after the car runs.

Air in the cooling system?

Car running to lean (notwithstanding comment above)?

Plugs too hot? I have some hotter plugs in it from a ingition recipe for stock motors, could that contribute?

Other?

How old is the thermostat?

In reply to BoxheadTim:

Should be fairly new (was replaced shortly before I pulled the motor).

I did test it, opens and closes nicely.

How old is radiator? If its partially clogged with corrosion,etc the car will overheat under load, but not cruising.

Sounds like the radiator to me as well. Give it a good flush, and see if that helps. Make sure the fans are working properly. Up hill will make the engine work harder to maintain speed, so more heat is generated over a given distance. Your radiator isn't doing a good enough job of disapating the heat.

I'm going to go in another direction - if the ignition timing is settable, I'm going to suggest the ignition is retarded too much, or maybe the vacuum advance is not functioning. That will definitely cause overheating. The constant load of an upgrade will really bring this effect to the fore.

checked your fan?

What is your definition of "cool" and "hot" ? This is important. As long as the engine temp doesn't go over 220, you're fine. Normally, the engine temp should be from 180 to 200. Without numbers to go by, you're just guessing. It's normal for an engine to get a touch warmer going up a hill or under a load, but as long as the cooling system is working properly it shouldn't get over 220 plus or minus a bit.

that is a good point. Modern cars' temp gages do not move unless cold or burning up hot. The needles on older cars move around quite a bit. The one on my fiat, I can watch it slowly creep up till the electric fan comes on.. and then it drops back down

I had this happen to me in a old Valiant I used to own, so probably not relevant.

I had the radiator looked at, got a new radiator cap, new water pump...I REALLY didn't know much about cars back then (and still don't) and flushed the system twice with new anti-freeze. Turned out, yes, it was running lean, but not for the reason you might think...tho I think it's the possible cause here. In my case, the only thing I didn't look at was the air cleaner, until it got so clogged the engine could not idle while sitting at a stop light.

If you hve a 180 'stat and the temp climbs to around 190 or so, I wouldn't be concerned. The Abomination (12A rotary Spitfire) with a 180 t-stat would get close to 190 on an AX course, it dropped right back down to 180 or so after the shenanigans. OTOH, a hillclimb would see 215 deg after ~2 miles of hard running. In that case, it really needed more radiator. Keep in mind that was also because of altitude, the higher you go the thinner the air, thinner air = fewer molecules to transfer heat. I learned THAT one the hard way in the Rockies.

About electric fans: over about 30MPH they are just along for the ride.

mad_machine wrote: checked your fan?

Check how your fan is mounted.

Had the same issue once, the fan was loosely zip tied to the fan brackets and when going up hills the fan would rest against the radiator unable to spin. I never could figure out what was wrong until the radiator sprung a leak. When I was fixing it you could see dents in the radiator from the fan hitting it.

he doesn't mention an electric fan.. the E21 has a fan with a coupling.

Fellas,

Sorry for the tardy reply here, life got in the way.

Radiator is pretty clean (inside), actually. No leaks or defects that I can "see".

I've replaced the belt driven fan with an electric one, mounted to the front of the radiator (pushing). To big to go behind it (water pump gets in the way).

Fan itself spins up pretty nicely, always goes off as the car heats up and doesn't stop until it gets below the setting.

Temp wise, the electric fan is set to go off at 180, and this it does (a little less than the 1/2 way mark on the temp gauge). When "hot" it's getting to the 3/4 mark, maybe a touch more - I'd guess that's around 220-240.

Timing if anything is a bit advanced (from stock), but probably not more than 2-3 degrees.

It'd be a shame if it's the radiator (it's a pretty nice unit), but if that were the case, seems to me that it should heat up all the time, not just under a slight load uphill.

Flat ground or down hill and it cools down just fine.

This baffles me (not that it takes a whole lot....).

Hmmm. I'd first stick a mechanical gauge on it (or even verify temps with an infrared thermometer) and find out fo' sho' what the temp is. If the stock gauge is going kerflooey, you could spend the rest of your life messing with this and never get rid of the 'problem'. Might be worth replacing the stock temp sender and see if that changes anything.

Fans are a lot more efficient pulling rather than pushing. I'd be inclined to start there.

integraguy wrote: I had this happen to me in a old Valiant I used to own, so probably not relevant.

Was there a guy in a truck trying to run you down for no reason? I seem to remember an over-heating Valiant in that predicament.

fan clutch?

In reply to gunner:

He's running an electric fan.

Another vote for a cruddy radiator. Are there any cool spots on it when the car is hot?