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Old 24 May 2015, 12:27 am
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Badglas Badglas is offline
Cool Cruiser
Join Date: Jul 2012
Location: Central Illinois
Posts: 493
Default Head Gasket Testing

Greetings to all! It's been awhile. I wanted to let you folks know about something I have run into when it comes to using a chemical test to check for exhaust gas in the coolant.

Those of you that remember me know that my grandson and I bought and repaired two PT Cruisers a couple of years ago. Both had been diagnosed with blown head gaskets at reputable shops by way of chemical testing. As I discussed in my build threads on both PT's, neither had a blown head gasket. What both had in common was a plugged radiator.

Over the last two days I have had two PT owners call me with overheating problems. They are similar, so I'll use one as an example.

2003 PT Cruiser that is driven a short distance daily by an older woman. It has been maintained very well and has 75,000 miles on it. The Check Engine light came on so she took it to the local dealer. It had set a code for a faulty thermostat. They replaced the thermostat, upper hose, and a shift solenoid for a total cost of $900. We are still waiting to find out why the trans sensor was replaced. The vehicle overheated the next day. She took it back to the dealer, who diagnosed a bad head gasket using a chemical test.

At this point her son called me. I suggested he have the test verified by someone he trusted before authorizing any repair. Two other reputable shops ran chemical tests and also pronounced the head gasket blown.

Call me a skeptic, but I did not think the head gasket was bad. The symptoms did not fit. When it overheated you could cool it down by turning on the heat full blast. It did not boil over at any time, and the system had been thoroughly purged of air. I suggested that the radiator was plugged. He then told me the dealer had replaced the heater core two years ago because it was plugged. I agreed to take a look.

This is where it becomes informative. I met him at his shop and ran the chemical test myself. It did test positive for exhaust gas. He agreed before pulling the head to replace the radiator. He ordered the $52 one from Rock Auto. He installed it today. He called to tell me that it no longer overheated no matter what he did. I went back to his shop to run the chemical test again just to satisfy my own curiosity. Same kit, same batch of fluid; no exhaust gases detected.

I have no explanation as to why this happened. Why would a plugged radiator cause a false reading in detecting exhaust gas? Maybe Nitro will way in.

What I wanted you folks to be aware of is that I know of four PT's that were diagnosed with bad head gaskets, none of them had blown gasket, all of them had a plugged radiator.

Happy Memorial Day!

2001 PT Cruiser Limited Auto Stock

"Political correctness is a doctrine, fostered by a delusional, illogical Minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a Turd by the clean end". (R.J. Wiedemann Lt.Col. USMC Ret)
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