`98 TJ Still Overheating

While you are waiting for the new radiator to arrive you may want to try using a cooling system 'cleaner' which is a bit stronger than a 'flush' to get everything possible out of the block and heater core.

Did you ever use 'stop-leak'??

The best way I have found for flushing a cooling system is with the use of a 'flush-n-fill' kit. It is so much more efficient as far as flushing goes there is really no comparison with the old style 'drain-fill-drain system because it allows you to force water backwards to its normal flow at a higher rate.

Prestone (and others) make a complete kit with a selection of tees, clamps,a radiator spout, and a doglegged .... ahhh.... connect-o-matic thing (female hose connectors on each end) If you have an old washing machine hose you can just buy the tee (99 cents) and a couple clamps (99 cents).

You might have been able to have the old one 'rodded out' and chemically cleaned at a radiator shop but it sounds like your old one was in pretty bad shape.

Your Jeep came from the factory with the old style "American Green" coolant. DC says you can still use this but they prefer that you upgrade to the new G-05 spec which has superior anti-corrosive properties. The only supplier to the aftermarket is Valvoline's Zerex G-05 brand in the gold jug.

Also please be aware that NOTHING made by Prestone or Peak (or most generic brands) meets either the new or old spec as all their products are DexCool or based on DexCool technology and DC specifically warns you against its use.

If you want to stay with "American Green' it is available from Valvoline Zerex brand in the white jug.

Finally I recommend that 50/50 premix never be used as there is always residual water in the block and 50% + 0% i always less than 50% and concentrations of less than 44% have no appreciable anti-corrosive effect.

The best procedure is to add the concentrate first and then top off with the appropriate amount of DISTILLED water, that way you know the final concentration will be.

Note: I am aware that Prestone claims on its label that you can use it in ANY vehicle. DC, Ford, Mercedes (who all use G-05), Toyota, and Honda (who have their own spec) say otherwise.

Great info- Thanks! In fact, I did use "stop-a-leak" or "liquid weld" or some other brand last week during my first drain and fill. This had nothing to do with the original overheating problem. Are these products bad for an engine? Would the flushing I did remove all the liquid weld?

The problem with stop-leak products is that they don't know when to stop so they try to plug everything including the water passages.

If you must try something the safest thing I have used is the powdered aluminum or brass stuff, you add a bit at a time until the leak stops.

I'm serious about the Prestone.... DexCool will damage your cooling system....

I may have missed the post where you said you checked it, but have you checked your clutch fan? Simply rung the vehicle until it is up to temp, and shit it off. Check the clutch by trying to turn the fan blades by hand. If you can turn it the clutch is shot, which will cause the fan to turn too slow when the clutch is trying to engage. Usually when running the heater cools the temps down, it indicates a lack of airflow through the radiator, but not always.

Chris

I asked about the fan clutch on that thing like twice already, he hasn't responded about it...

Troy

Sorry dude- fan clutch seems fine. Mild resistance at cold startup, once engine is warm and cut off, fan stops too.

How does > I asked about the fan clutch on that thing like twice already, he hasn't

Valvoline clearly labels its Zerex brand coolants in large letters on the front label and as it is the only supplier of G-05 you most likely haven't got it. Visually it comes in a gold colored jug and is pale yellow in color.

If you want the old style American Green Zerex now calls it Original Formula and it comes in a white jug.

If the label says Prestone or Peak it is DexCool or based on DexCool.

FWIW: I found Zerex G-05 at PepBoys

Is it overheating while idle or while running? It could possibly be the head gasket if all else checks out, after you install yer new radiator. I just finished chasing down an overheating issue on my xj, and my gf's tj. My tj hasn't had any cooling issues yet but I'm suprised after all the muddin' I do.

Troy