'96 cooling - issues
 

PO said he always ran 50/50. what it had was water with some. light crud in there. I flushed with water & refilled. Drove for two days with and without heater and repeated whole process again. Heater never did work. I did all that to make sure any soot, grit or dexcool was gone and I could move on to Prestone Green stuff. Everything was fine for two months until I fixed the 4WD front axle actuator. To test drive I went "hot rodding" for a couple of minutes in a grassy spot near home & blew the water pump.

New water pump in and repeat flush process just once. All OK so add 100% prestone again. A month later it shot up to "HOT" fast and often. add 180* thermostat. Good for two weeks then sparatic hot spikes. Bad Thermostat? Mebe. Replace with 150* thermo. 2 weeks until repeat spiking. Now loosing coolant regularly. First I thought a bad seal on the thermo housing. Then (after scrubbing both sides) the rusty looking leakage was all over the pump. Top hose is always super hot and hard. Bottom one was OK. I diagnosed a clog in the radiator. I took it to a radiator shop and the owner put his hands all over the core and found a cool spot near the low/return hose. Probably a nasty clog internally. New radiator time.

This post got way too long. In hopes that somebody has any ideas that I did not cover with this weird flow issue; I will move the last part to a much shorter post in hopes of getting on the road again. BTW the heater did start working 6 months ago (at the beginning of summer) hahaha

As part of the flush I usually drain everything I can and fill with white vinegar and run it for a couple hours then start with flushing it with water. Vinegar seems to be the best cleaning least caustic of the coolant cleaners - I don't feel so bad draining it onto the ground. I do end up spending a lot of time flushing with water to get the vinegar out. Then I flush the tap water out with a couple flushes of distilled water. I use the Prestone Green for everything from my 1950s farm tractor to my 2002 F250.


At work our diesel mechanic uses dish washer detergent to flush heavy equipment.

Good Info

Thanx!

I don't see the original post or concern, but with a 1996, I assume it was a Dex Cool question. Two days running with clear water is not enough to flush out the brown solution that is formed when Dex Cool and green coolant mix. It is a good start. It may have contributed to the failure of the water pump. The pump is trying to pump a sludge rather than a clean mix of water and coolant. It wasn't designed for that.
With the bad experience I had with a 1994 Chevy V8 in a Impala SS where I tried to 'upgrade' my coolant from the original green coolant to a long life 5 year Dex Cool. The sludge goes everywhere. It is in the passages in the engine, the heater core, the radiator and the plastic reservoir. That means every nook and cranny. I did eventually purchase a new plastic reservoir because it was the most obvious and blatant symbol of the sludge...... and it was the cheapest and easiest thing to replace. I should have replaced the radiator, also. The heater core is also one of the main things affected and you don't notice it until it turns cold. That is one of the hardest items to replace so it is most ignored in the entire cooling system. I removed the heater hoses at the water pump and used garden hose pressure/not high pressure. Flush the heater core: first one way and then the other. Reverse flushing is very beneficial especially in the heater core.
The Prestone company makes a cooling system flush. Be sure to follow the directions carefully. Remember the trick of removing the drain plugs aka the knock sensors on either side of the lower engine block to get the coolant out of the bottom of the engine. Yes, you may have to gently use a screwdriver blade to break the crud clogging the knock sensors drain hole. That is a sign of the corrosion in the entire system.

Thanx Jim
This is sounding more like a disease than a simple oil (coolant) change. I heard stories about issues with Dexcool but none as thorough as yours. I really thought that my process: "flushed thoroughly (while running) with water & refilled. Drove for two days with and without heater and repeated whole process again" would resolve any lingering issues before using the Prestone 100%

With a 21 year old truck; the thought of using chemical flushes (even Vinager) seems like a corrosive solution to a aged and fragile system. Taking the engine plugs out and replacing the reservoir sounds beyond thorough. Hell, if I had any idea this would be so much trouble to switch to "Green" I would have just used Dexcool and hoped the PO didn't start this problem. The fact that it had that silty, slimy sludge in the water tells me this was an issue B4 I took ownership.

Now here I am trying to figure out issues with the "quick connects" on the brand new radiator to accompany my brand new Water pump. The engine has been drained 6 days now. I'm thinking that maybe I should go out and buy Dexcool. But then if this "disease" has already begun (and surely there is still green in there somewhere); would I just be putting the disease on the "fast track?"

If I had any idea 3 weeks ago that I was going to replace the water pump and the Radiator together; that would have been the time to use a chemical or vinager flush. Now I really don't want to "dis-lodge" any gooey crud unto my new radiator. Once I figure out these connectors I think I will drive on distilled water for a week or so. That should flush out most of the green stuff etc. I am open to suggestions B4 I fill it with anything. Thanx

I am gonna back flush the heather core today & see about getting the oil & tranny quick connects working. I would like the opinion of those following this thread about going back to Dexcool or staying with the Green Prestone.

Your issue has nothing to do with what type of coolant you use, so use the type that makes you happy; just do not mix them. Find the source of the leak and the location of the blockage.

I agree with Rriddle3. Both types of coolant have their advantages, and both can do the job equally well, but you need to resolve the leak and blockage problems. If you have crud blocking passages, you're likely going to need more than just water to dissolve them quickly. You may want to consider taking it to a shop to have a professional flush done.

That would have been a real good option a month ago, Now I have a new radiator & pump. 5 days w/distilled water seems smooth & clean so far

Thanks everyone
 

Loved the replies to this post. Thanks for the tips my 96 just started overheating and heater not working. I am going to try the vinegar flush and get a good flush after that to try to resolve problem.