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Old 05-04-2003, 12:16 AM
95E320cab 95E320cab is offline
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Join Date: Jul 2002
Location: Dallas
Posts: 330
Woes of pressure washing engine

I have already solved the mystery. But here's the story.

Last fall i had to replace my water pump. Paid an indy about $700 to do the job including a serpentine belt. When I went to pick it up they had it running with the hood up and the A/C on. Temperature was a little higher than before the pump failure. I noticed the overflow tank had green coolant in it. I had picked up a gallon of MB antifreeze and left it in the floorboard but they didn't use it. I asked if they had replaced the thermostat and they had not. I was ready to get the car back so I just took it and drove off slightly p.o'd.

Noticed over the last months that the temp ran slightly higher than before and attributed the casue to a too rich ratio of coolant to water.

Last weekend I felt like doing something to the car but there were so problems so I decided to "detail" the engine compartment. I have a 2200 psi pressure washer, so I mixed up a solution of degreaser, covered electrical connections with plastic wrap and rubber bands and got after it. Didn't use much water or degreaser - just enough to rinse off the surface dirt. Turned the throttle way down on the sprayer so there wasn't too much pressure blasting around.

Afterward I removed all the plastic and dried and wiped with a towel. Looked great. Started her up and ran with no problems.

Later this week i noticed the temperature really going up with the A/C on in slower/stop-and-go traffic. Would reach as much as 110 C. Started to suspect the thermostat. I had ordered one a while back so I called the indy that did the water pump. I asked him to take care of a flush and thermostat change gratis since they didn't change the stat out. He agreed somewhat reluctantly.

When I picked it up, same scenario except that the A/C was not running during their test. I turned it on and the temp rose rather quickly to 110. I then noticed the culprit - the fans weren't running. The tech switched the wires on the A/C fan switch and the fans kicked in on the signal from the engine temp sensor. So he surmised the A/C fan switch was shot. I brought it home and looked up the part on line - $25. Not bad. Called the Dealer - $53 but no waiting. Went out to the garage and started looking at the connections. Noticed the switch plugged into the dryer. If I just unscrewed it I'd loose all my R134. So I called the dealer back and got on the phone with one of their mechanics. Ceasar told me horror stories about $4,000 evaporators and scared the pooh out of me. We discussed a little further before he suggested I check the fuse. Duh. I guess I got some water puddled up in the engine bay and shorted out the circuit. Fuses saved the day and I learned a lesson or two.

All's well that ends well, but I had a bad feeling about using that pressure washer. Or anything else spraying water under the hood for that matter. A more experienced DIYer would have probably never gone as far as I without checking the fans, let alone the fuses. Live and learn, dumb a**.

Last edited by 95E320cab; 05-04-2003 at 01:11 AM.
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