Previous question for context

TL;DR: My 2001 Pontiac Grand Am SE had a flashing check engine light and I found oil in the coolant.

A family member took the car to a mechanic this week. He checked it over and said that it was a problem with the ignition (which he fixed). As I didn't drop off or pick up the car personally, I don't know exactly what was wrong with the ignition, but I'm wondering if I should get a second opinion from another mechanic. It seems off to me that all that was wrong was an ignition problem, given that there was oil in the cooling system, and I don't want to drive around a car that could go at any time.

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    About the oil inside the coolant reference the following: mechanics.stackexchange.com/a/6447/2881 – cinelli Jun 27 '13 at 21:02
  • Yes, your answer made me hesitant to accept the mechanic's assertion that it was just a problem with the ignition. I'm therefore wondering if I should get it checked out elsewhere... – Meta Jun 28 '13 at 12:13
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    What he said makes no sense. I would bring it to a reputable shop. – cinelli Jun 28 '13 at 18:37
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    I wouldn't beleive it. There may very well have been a problem with the ignition but I doubt that's the only thing wrong with it if you've got oil in the coolant. – Sam Whited Sep 26 '13 at 0:51

I think he's maybe half right...

A blinking check engine light is a misfire. Replacing spark plugs and/or wires would probably fix it. But that's fixing the symptom, not the cause (potentially, based on your information of oil in coolant). A bad enough head gasket or warped head (do not replace the gasket without checking the head for cracks and warp! ) could easily foul any number of plugs. There is also the possibility that instead of a head gasket it is an intake gasket (very common on Chevy V6s from this era). If the intake gasket is bad enough, you can get oil in your coolant and mess up some plug wires as well.


coolant pressure shouldn't be more than 15~20 psi, oil pressure will be 40psi + Could be oil seal was leaking into water pump which is why he did ignition (I thought they had external trigger though?) Reading previous question/answer I would concur on intake or head gasket leak Personally I think you should get a second opinion, get compression and leakdown tests which will help narrow down the area Changing head gasket is do-able but not something I would recommend, I've only done one and it took 'days' (well felt like it LOL) someone with 'practice' can do a much faster job


i think you can trust him if he said ok, anyway the good test in your case before summer is to put the coolant into pressure, with a special pomp first for check any (small) coolant drop.

After that and a purge put the car into high idling, wait for fans at his second high speed: Car got to pass this test with no heavy idling. After engine cold, the next day, don't start the engine but check if the oil don't have a bit of water (on top because unmixable) If this two small tests are ok this will bring you confort about cylinder head gasket or coolant problems for next months for sure.

Note this, it exist a chemical test which is fine for testing smalls or small begining of cylinder head gaskets problems, by chemical detection of carbon dioxide into coolant.

In all case, and i say that because i live into high mountains, do all liquids engine levels and go drive for 40km into mountains like ski stations and you will be fixed about cylinder head gaskets: If all is fine, this will be for thousands km or miles. If it idle too much, just come down go to mecanich :)


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