'88 Voyager heating problem (no simple fix)

My Dodge had a partially plugged heater core. I took the heater hoses off the heater core pipe in the engine compartment, hooked it up to a pressure washer by fabricating a piece of heater hose and power flushed it for 2 minutes, starting with low pressure and slowly increasing pressure. Lots of gunk and scale caome out. Now I get so much heat I have to crank down the window a bit.

Somehow coolant is is getting past the thermostat, the fact that it never warms up, and the temperature falls off when you drive (airflow thru radiator) means the thermostat isn't blocking the flow of coolant as it should.

Perhaps you have the wrong size of thermostat, or the thermostat housing is corroded and letting a lot of coolant leak past the thermostat?

Lastly, it is not unknown to have three bad thermostats in a row!

I had it happen to me on my '93 Aerostar.

Good luck.

tell us where you are buying your themostats from so we know not to go there

1 thermostat from Canadian tire (fail safe thermostat), another regular thermostat from NAPA, and the last one was straight from the dealer.

I have seen bad batches of thermostats too.

I was also told, but don't know for sure that if you try the thermostat in your fingers to see if it opens before you put it in, that doing that can wreck some of them. Something to do with a wax pellet type, but I can't really see how this would harm them.

You are describing a wide open t-stat anyway.

Mike

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

Whoa! wait a second Mike! I have heard of "hot blooded" types but come on now....some thermostats are rated at 195 F (which means they fully open at

195 F) I don't think you want to be holding anything in your hand at 195 to see if it opens! Yikes! can you say: "Third degree burn" When I first bought my brand new car with the alum. block back in '89 from the Chevy dealer it had a thermostat that was partly opened at room temp. and won't allow the engine to heat up to operating temp. I too didn't have heat in the car. After I bought a replacement from NAPA now I have to turn the heat down on any rides over 25 minutes long. Before you install a thermostat look at it at room temp and it must be closed. Some have a tiny hole in the diaphragm about .030" to both prevent pressure buildup and allow a very small amount of water to flow past the thermostat to warm up the sensing element so it will open when the water is hot. If you really want to play around, then put the thermostat in a pan of water on the stove and turn on the burner. Just before the water boils at 212 F the thermostat should have went from closed to fully opened. You should be able to watch it opening as the water is heating up and you can take the pot off the stove when the themostat is fully opened at 195 F before the water boils at 212 F. Bon-a-petite-with a sprig of parsley thems good eating

"Frank" wrote

I think he means just shoving the COLD valve open against the spring's pressure.

I guess he figures (theoretically) that since the "captured" wax pellet is designed to expand and push the valve's rod out of the sealed chamber, thereby opening the valve, physically pulling the rod out by pushing the valve open could create a vacuum in the chamber, possibly sucking in air that shouldn't be there.

what are the chances the 3 brands you bought are from the same oem and the same bad batch? how many manufacturers of t stats are there? i bet not many. "MasterBlaster" > it opens!

LOL!

I might be a Crazy Canuck, but I am not 'that' crazy...

I was meaning that some folks have a tendency to take the t-stat out of the package and physically force it open just to see if it moves.

I know I have and I think I did it on my last t-stat. Mine won't heat up well at all and sometimes goes way too hot, then suddenly drops down to cold. I know I have no air locks in it.

I am going to go get another one before it gets too cold and put it in to see if my inside heat will get warmer. It is pretty cool right now. Well, I can still drive on the highway with the soft top with no gloves on at - 5C, but any colder and no way.....

Mike

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

Frank wrote: