Cracked head/block?

Hello all. I just joined this forum today though I have gleaned some information from it in the past.

 

I bought a Legacy with what I believe to be a cracked engine block or head. I plan on replacing the engine, but want to be thorough before I chuck it! How does one diagnose this for certain?

 

Symptoms:

Constant overheating

All coolant seems to be pushed out of motor/radiator

After getting hot, the overflow tank shows a really thick foamy head

If you start the car (cold) with the radiator cap off, coolant shoots out of it.

Has a weak idle, sounds like a miss. Computer confirms miss in No 3.

 

Thanks in advance!

-Nathan

Hey there, fellow Nathan or rather legacy member. You have a blown head gasket plain and simple. You will need to yank the engine and tear it down to see which HG or both failed. The coolant issues are due to the coolant being pressurized by the exhaust gases that should be sealed in the cylinder by your HG.

 

If it was driven extensively while overheating you will need to have the heads and block worked over (decked and lined bored etc) You may be able to find a used engine for similar price with lower miles to get you up an running again faster than waiting for a rebuild.

Thanks for the response!

 

How can you be so sure its the HG? Couldn't a crack in the head produce the same symptoms? If its the HG, I'll fix it, but if a head is cracked, I need to try to get to the pick and pull this weekend.

 

Last time I had a set of 2.5 heads reworked it was $400. Guess I'll pull the heads and take them to the shop.

It could be a cracked cylinder allowing gasses to enter the jacket and thus pressurizing the coolant, cant be sure until you tear it down. More commonly the HG will fail and yield this symptom, if you do have a cracked cylinder then you have other horrific problems Also have you checked you oil I only ask b/c if coolant is in the oil and has been for a while you might want to consider a bottom end rebuild, bearings and oil/coolant smoothie done jive well with one another.

Yeah, I've kept an eye on the oil and their is no indication of mixing with coolant. Good thought tho...

 

I'll pick up an engine this weekend if I can find one, then tear this one apart. With any luck I'll have a salvageable core for a rebuild!

 

Thanks again for your thoughts, gee-otto.

Yeah, I've kept an eye on the oil and their is no indication of mixing with coolant. Good thought tho...

 

I'll pick up an engine this weekend if I can find one, then tear this one apart. With any luck I'll have a salvageable core for a rebuild!

 

Thanks again for your thoughts, gee-otto.

 

 

If your oil is clean you might very well have a cracked cylinder now that I think about it that either way you are on the right path to the fix. If you can pull and EJ for cheap and only need to do head work you could come out with a working motor for a good price.

I picked up a 2.2 from a 95 Legacy for $300, 150,000 miles. If the 2.5 heads check out, I may put the DOHC heads and intake on the 2.2 in while. Either way, I am looking forward to some better mileage soon, my '71 Ford truck is eating my wallet!