I bought a 2002 XC70, very clean, great price. Next morning I started the car and it ran rough for about 30 seconds. Then "Low Coolant" , and "Check Engine" lights came on. I took it to a mechanic, and he said cyl #4 had misfires, and I have a blown head gasket, & don't drive the car.

I took it to another guy who checked the spark plugs, the oil, the coolant and smelled the exhaust, and said I don't have a blown head gasket. Although spark plug #4 was browner than the others. He swapped #2 & #4 plugs and coils and said drive it for week, then come back and we'll check the new #4 plug. He recommended I put stop leak, in the coolant in case there is a small crack in the gasket.

It uses 1 cup of coolant a day, with no signs of leaking, and runs great!
Is there any way to tell if head gasket is blown with removing the head?
Is stop leak is a good idea?

 

Stop leak is a terrible idea. Do not use that mechanic again.

You can check for combustion gasses in the coolant with a test kit like this one

A compression test, or better yet, cylinder leakage test and also check the cylinders. Or a pressure test of the cooling system while looking in the cylinder for coolant.

This is all basic stuff for a professional, so if the first mechanic didn't bother, I don't know if I'd go with him again either.

 

Thank you. It all makes sense. Sounds like stuff I should have done before I spent my savings on this car. What is the test kit that you spoke of? Is it okay to continue driving the car?... my only car.

 

Click the link above for the test kit. It is a fluid that turns color when it comes into contact with combustion gasses. So you take the coolant reservoir cap off and install that device with some fluid in it. Then you run the car for a while and squeeze the bulb to draw the vapor from the reservoir through the fluid. If it changes color, exhaust gasses are in there, indicating either a blown head gasket or cracked head or block.

 

Great! Thank you.

 

Got the tester, followed instructions having coolant level 2" - 3" from top, and started engine. After about 1 minute coolant started overflowing. This morning, the coolant level should be much lower, so I'll try it again without putting any coolant in.

Question - Instruction say to take radiator cap off and put the cylinder into there. Should the coolant reservoir work also?

 

Yes. There is no radiator cap. The instructions are generic.

 

Hope the stop leak didn't plug anything that it should not have. That is why EST6 suggested not using it and I agree.