Possible Overheating in 4wd?

[smallwwb]

I have an '88 DL S/R 5spd 4wd with 211k.

Just did timing belts, water pump, flushed radiator and put in new coolant. Thermostat seems to be functioning properly, fan comes on as it should.

When I'm doing light 'wheeling, or stop-go traffic for periods of time, the temp gauge runs up near the Red mark but never quite gets there.

Is this bad? I've heard the gauges aren't that accurate.

[off-road-knight]

yea today was the first day I drove my 87 gl10 turbo wagon and it seemed to be at the halfway mark on the digi-dash in FWD but after some AWD it seemed to knock up a couple notches, a solution to this would help me out aswell

[SuBrat84]

Normal operation temp is ~190 degrees Fahrenheit. I think the red mark is ~220 or 230 Fahrenheit. (Someone correct me if I'm wrong.) Even still it shouldn't really be going much above half way. It's possibly the thermostat is on it's way out and not opening as soon as it should. It's possible there is some blockage in your cooling system. When you noticing the needle moving up try turning your heater on full blast and see if that brings it back down.

You could also try feeling around the radiator to see if it's getting "hot spots." Hot spots would indicate blockage in the radiator itself. You could have a failing temperature sensor..

 

I had a brat that did what you are talking about.. but only during hard wheeling under 10mph. I think it was an issue with the old radiator / desert heat.

[SuBrat84]

Also, since you just did a flush and fill.. you might have an air bubble. Wait until the car is cold. Take the radiator cap off. Start and run the car until it is up to operating temp (so the t-stat opens and coolant starts flowing) and then top off the cooling system to help avoid air bubbles. (if you did this correctly in the first place, it's probably not the problem.)

[Ricearu]

is the thermostat dealer or aftermarket? I had all kinds of wierd cooling issues with "the left one", installed the dealer one and it is now cake. here is a comparo pic, the brass awesome one on the left is the dealer, the right one is "oem quality" from allimport auto parts.

 

 

[smallwwb]

The thermostat is stock, or was replaced by the previous owner with a stock one. I did the old pot-o'-water boiling trick when I did the t-belts/water pmp, and it opened as it should have. Don't know about the radiator. When I flushed it I thought the amount of coolant that came out seemed a bit low...It doesn't have any leaks. Got the air bubbles out when I put it all back together.

 

But yeah, desert wheeling at under 10mph is where I got the hottest temp too.

How exactly does one feel for hot spots? It's a little tight in there, what with the fan and the belt and all.

 

What about a 160 or 170 t-stat?

I don't want to throw money at this motor, as I'm planning to do a swap in the next year.

[SuBrat84]

It's a lot easier to feel for hot spots if you pull the fans off. You might try a cooler t-stat and see how it acts... How are the fins on the radiator? Are there a lot that are flattened down? or are they all fairly straight and open still?

[WoodsWagon]

I'm assuming you have a belt driven clutch fan and an electric fan? The thermo-switch in the radiator end tank can go bad, and the electric fan won't turn on. Make sure the fans are actually running.

[smallwwb]

Radiator's in great shape on the outside. No bent fins, no leaks, etc.

My car has the A/C removed, so no clutch fan, just the electric. I could always add it back, but that creates drag and robs hp/mpg. It makes a noticeable difference without it.

I'll try checking for hotspots, and look into a cooler t-stat. Not too much of a problem right now as it's winter.