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Diagnosing Engine Problems

A few weeks ago my Mom’s 2008 Madza 3 ran hot and wouldn’t restart. We eventually had the car towed to a local automotive shop to diagnose the problem.

They checked the car and said the thermostat was stuck and probably needed to be replaced along with a head gasket -the cost was $1200, but once they replaced these items the car still wouldn’t start. Then they said the whole motor needed to be replaced and it would cost $4156. Oh my goodness ! Needless to say we are outraged ! Can engine problems be diagnosed before putting on new gaskets?

Please help !

Can I assume that a compression test was performed as part of the diagnosis?

Did the shop lay a straightedge on the cylinder head and block to determine if anything was warped?j

Did the shop send the head out to be “cleaned up.” That’s often done as part of a head gasket job.

Did the shop do another compression test after the repair?

FYI in some instances engines that overheat and stop running can’t effectively be saved.
It happened to my neighbor’s car. His water pump physically broke on the freeway and the engine stopped running. I diagnosed the car. It had extremely low compression and squirting oil didn’t change the readings at all. So obviously the problem was top end. I told him that in my opinion his motor was not worth repairing. He later had the car scrapped, as it was an older V8 BMW, which would have been extremely expensive to repair.

You are right to be outraged.

Yes, absolutely. Any mechanic worth his salt would have been able to definitively diagnose whether the headgasket was truely damaged, which it may have been, and also whether replacing it would allow the engine to start again. The condition of the cylinders might be arguable, but not the ability to start.

Honestly, I’d have it towed to another shop. There’s a good possibility that when replacing the headgasket they mistimed the valves. If the valve timing is off (more than slightly) the engine will not run. They’re probably just unwilling to admit that they screwed up the valve timing.

But before I commit to that…exactly what is the engine doing when they try to start it?

Yes a compression test was performed but I don’t think it was done prior to installing new gaskets . I’m not sure what they did after they installed them we were just called and told “the car still won’t start” you need a new engine . They did also send the head out . Don’t know about the second question.

You need to find out why they say it won’t start. What’s it doing or not doing when they try to start it.

@thesamemountainbike has some very good points. If the valve timing is off by a few degrees, the engine may not start. That would affect compression.

Ask the shop to have their best and most experienced guy visually confirm that everything is reconnected and that the valve timing is 100% correct.
Also make sure that there are no blown fuses, weak batteries, etc.
Perhaps fault codes need to be cleared and a relearn procedure performed.

That’s a good question but I don’t have an answer. That wasn’t communicated to us. They just conveyed that something got so hot it melted, etc. I’m assuming it was something they observed on the engine. I think at that point he was trying to explain why the engine needed to be replaced.
By the way we have removed it from the shop and are seeking to get our money returned due to incompetentcy !

Did they mention the word “bearing”?
I may have to “eat my words”. If the engine got so hot that it damaged a crank or rod bearing, it could have seized when they tried to start the engine back up.

Thank you guys so much !

Nothing about bearings was mentioned to my knowledge, but my husband did just share that they said the car would turn over but wouldn’t start after the gasket replacement.

In that case, I suspect they screwed up the valve timing.

Sincere best of luck with this. At least you know that you have a good headgasket now and the engine will turn over. That, to me, means the problem should be repairable and you don’t need a new engine. That also means there are no seized bearings.

Thanks again !!