Runs Hot!!!!!!

[RonVan]

My 90 Suburban Runs hot (230+) in the summer and pulling long hills. Lots of black smoke until I manully Shift My 700R into 2nd gear. Some loss of power. I have considered placing and aftermarket fan type oil cooler in front of the radiator and rerouting the existing oil cooler line to the new cooler only. There is not a whole lot of room for any aftermarket cooler in front of the radiator.
Anybody help?????:confused:

[84 Convert]

Black smoke indicates too much fuel. I have found with my new 190hp pump (DB2-4911) that when my exhaust has a lot of black smoke, my EGT rises quickly which also raises water temp. You may also have other cooling problems like your fan clutch and thermostat. Also when the head gaskets were blown on my truck, temps went way higher than I wanted when towing(at the time I didn't have enough pump output to have black smoke).

I would suggest getting an exhaust temp guage to see how things are going there. Also, definitely check your intake plumbing for restriction. not enough air through the engine will make it difficult to keep cool. I'm not really sure how one would check the fan clutch other than listening for it to kick in above ~200*, also, steal your wife's candy thermometer and boil the T-stat to see when it opens. Your radiator may need to be rodded out if it is plugged. The way to check the radiator is to fill it with water with the hoses off and the lower outlet blocked, then unblock the opening and the radiator should empty almost immediately.

I really think the excess fuel is your main problem. Whether it could be caused by pump or injector malfunction I cannot say.

Hope this helps.

Gregg

[RonVan]

Thanks for the info. I will check into the fuel consumption. I recently installed a 180 degree t-stat, which helped. I will let you know how it goes.:) :)

[john8662]

What is the condition of your radiator? Look down into the tank on the radiator with the cap removed and see what the condition of the coolant is. I'd also suggest draining a bit of coolant from the radiator, enough so that you can start seeing the tubes/rows in the tank. Observe the condition of these tubes, if there is buildup around or over, then you're due for a rodd out.

A 180 stat is a good start, but make sure you've got the right stat. The Robershaw type extra duty stats do the trick for these engines, they also look like the factory stat that came out (which is ~195).

How much smoke does the engine make?

If black when the engine is getting hot, then you may need to look into disabling the EGR system, which could be robbing your engine of fresh air.

Check your fan clutch, visually inspect, look for wabbles, etc. When it's bone cold, you should get resistance from the clutch/fan when turning manually, if easy to spin, it's probably bad, should be hard to spin cold.

[RonVan]

Thanks.....Radiator looks fine and the t-stat is operating fine. The black smoke is only when under intense load...as in climbing highway mountain passes.

I will check the fan clutch.....that sounds like a possiblity. I have considered aftermarket oil/tran oil electric fan cooler to place in front of the radiator. There is not a lot of room up there so that will take a little modification, but could be an option. Perma-cool has several different types.

The engine has 216K on it and has never been into as far as I know. Could be time to address injectors and pump, right? Would that make any difference in the engine running hot under load?

[RonVan]

John8662,

I took your advise and checked the fan clutch. i can move the fan with one finger and no arm muscle. There are free spots and other areas that have just a touch of resistance.

Does that fit the description of a bad clutch?
:eek:

[DmaxMaverick]

Could be.

Is this on a cold engine, like first thing in the morning? Is there any sign of lube leaking from it, like oily/grimy spots? Sounds like it is either distorted or broken inside, or has lost some fluid. If the engine and clutch hub is warm-hot, it should be very smooth with slight resistance throughout rotation. You could put a heat gun (or a propane torch, but only lightly) on the bi-metal spring at the front. Once the temp gets up to 130-150

[RonVan]

Yes......cold engine first thing in the morning. No visible signs of leakage. Nothing changes when it is warm.
I will replace it and go from there.

Thanks:o