Overheating problem '97 TJ

The fan clutch sounds probable, and I will probably flush it too just to be safe but the antifreeze in it is only about a year old and still nice and green. Maybe it's too strong a mixture and I need more water.I will get a bottle of the Redline Water Wetter too just to help out.

I will consider a heavier weight oil also, i'm due for a change now anyway. Too bad Wally-World only carries Valvoline full synthetic in 10w30 so i'm going to have to go to a 'real' parts store like Auto Zone. (sic)

Shawn

What about a possible water pump problem Bill? He did not mention any unusual noise but that doesn't always happen.

I would (and did) install one of those $3.99 Flush-N-Fill Kits in the heater hose. It is remarkable how much junk it can flush out of a motor/radiator.

I would skip the water wetter. DC advises against it.

Make sure you get old fashioned 'American Green" or Zerex G-05 antifreeze and not the Texaco-GM "Dex-Cool" based formula which have a reputation for clogging and eating radiators metals.

The concentration should be 50-60% antifreeze in your area. Less offers little corrosion protection.

No strange noises so far. Seems like this is only a problem when the A/C is on and i'm idling in park or moving at very slow speeds. I can and have cooled it down by increasing RPMs while sitting still in park. It has been the hottest it's been here all summer recently. It's been 85F or higher and while I know that's nothing compared to Arizona or Florida it is damn hot to us temperate climate people.

I'm curious to the reason DC doesn't like the water wetter. I never heard anyone refer to it before.

And yes I am staying a far and wide path around the Dex-Cool stuff. I used that once on a car and regretted it dearly. I might as well have filled the f-ing thing with battery acid for all the damage it caused. My '99 Merc. Cougar came factory with it, so I left it alone. Maybe thats the key, unless it's put in at the factory never try to use it.

And yes I usually run 50%, but with the color of it now i'm worried it may be a lot higher percentage of antifreeze than water. Hose water is good to flush with but does anyone prefer distilled water to fill with?

Oh, and lastly I wonder if I have a sticking thermostat or maybe a bad radiator cap? I heard one noise that I think was the rad. cap letting go when it overheated once...

Shawn

There's no way I'd ever switch away from the '97 TJ's factory recommended 10W-30 to anything as heavy as 20W-40 or 20W-50. The 40 and

50 viscosities those operate at when warmed up are more difficult to pump through the engine's oil journals than is necessary and just makes the oil pump work harder. Plus the 20W viscosity it is before it warms up is harder to get pumped into the engine when it's cold which can cause reduced lubrication at startup, which is where much of an engine's wear comes from. Leading oil manufacturers are now even recommending 5W-30 over 10W-30 since it gets into the engine faster at startup yet it is still a good 30 weight viscosity when it gets up to normal operating temperature.

On your coolant and water mixture, it should be no stronger than 50:50. The more antifreeze used, the less efficient the mixture is at cooling the engine.

Jerry

Endo wrote:

The dealers here use Mobil 1 0W-40. I don't think I have ever seen a 10W-30 on the shelves; 10W-40 is the norm.

Dave Milne, Scotland

Sounds like the pump is turning then but the problem was there wasn't enough air flowing through the radiator. The Ohio Valley weather isn't always fun, it may be only 85 degrees but the humidity is also 85 percent.

I assume that DC doesn't like the additives as there is an increased possibility of unintended chemical interactions whenever you start dumping stuff into a complex piece of machinery. They say it isn't needed.

With the new antifreezes you have to use distilled water to get the greater benefit. I just flushed my WJ and I thought it was worth 79 cents/gallon for the distilled water. I got the "new" DC approved antifreeze (Zerex G-05) and was only able to find it at Pep Boys which is across town (in Cincinnati). It is NOT available at Auto-Zone, Advance Auto Parts, NAPA, Wal-Mart, K-Mart, Target, or Meijer. They carry Prestone or Peak. Zerex G-05 is about the same price as "American Green", I paid $9.99/gal

I've not looked into any prices but my WJ has an electric fan that is temperature controlled.

Thermostats and radiator caps are cheap. If I was having problems I would replace them as a matter of course.

As far as oil is concerned I am a great believer in the synthetics and synthetic blends. They flow more easily, clean better, increase mileage, and decrease emissions. They sometimes cause a drop in oil pressure because greater fluidity (reciprocal of viscosity), they flow so much easier than Dino oil. (You will recall that an oil pressure gauge measures the resistance to flow coming out of the pump). I run 10w-30 in the WJ (and

5w-30 in the Audi) but have no philosophical problems with using a slightly heavier multi-grade oil. I used Rotella-T 15w-40 or Pennzoil 20w-50 for many years and would not expect any problems in an 8 year old vehicle. I will cause your gasoline mileage to drop.

Our 'new' fan clutch just gave up the ghost. They (DC) are selling really crappie parts these days. Ours is only about 4 years old.

To test the fan clutch, heat up the engine fully and have someone shut it down while you watch the fan. A working clutch will stop the fan almost instantly. If it keeps spinning, replace. Or shove a screw in the SOB to make it a fixed fan like I think I am gong to do. If their crappie parts only last 3 or 4 years, screw them.

I would get a cheap hydrometer to check the antifreeze. Playing a guessing game with it is a sure way to destroy the engine. Too thick will overheat, 50/50 is best for all round use.

'I' sure wouldn't swap oil types unless mine turned into an oil burner. We have over 300K on ours and 10W30 still only uses a liter between changes.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Endo wrote:

Jerry and Mike are right. That said, I usually run somewhat "stronger" coolant, in case there is a loss and I have to limp home after putting some Dasani or Evian in it. The best place to store extra coolant, is in the cooling system.

Earle

I dont know if this is related but my brother-in-laws TJ will read hot from time to time and the oil gauge will go to near zero and the fuel gauge will screw up by showing about half what is actually in there. His problems sounds electrical to me but I have not checked it out yet. Be interested in finding out what is wrong with yours. My 01 TJ overheated after I rearended a Dodge truck and pushed the shroud into the fan! Ha Ha

David Short