[SubaDrew87]

Could someone please point me in the direction of the answer for sanitys sake! My car started overheating so I replaced the following parts in order.

-thermostat
-water pump & timing assembly
-all hoses that carry coolant
-radiator cap

Then I decided after 3 mechanics swore that it was a blown head and doing my own diagnostics to confirm it was leaking to do the following...

-head gaskets & bolts (felpro permatorque)
-exhaust gasket
-intake manifold gasket
-throttle body gasket
-knock sensor


Ran for the first time sputtered a bit, ran awesome then started overheating and smoking worse than ever before. The majority of its coming from the exhaust down pipe directly beneath the head. It's all on the passenger side too, the driver side isn't leaking at all. Coolant is also leaking down and forming a puddle of coolant under the oil chiller and filter.

Any suggestions would be greatly appreciated I've been 2 months into working on this car and I'm determined to fix it.

 

[Inactive_55959]

Does your car have the original plastic radiator? Those are known to fail at around 100k fairly reliably. Also: when you did the head gaskets did you have the heads resurfaced/checked for flatness?

 

[Easy Fixer]

Pressure test the system

The very first thing to do is pressure test the system. Will it hold 15 PSI. If it won't, find the leak. If you are lucky, its a hose. If you are unlucky its a cracked block or engine gasket.

 

[SubaDrew87]

Does your car have the original plastic radiator? Those are known to fail at around 100k fairly reliably. Also: when you did the head gaskets did you have the heads resurfaced/checked for flatness?

Replaced the original radiator with a solid aluminum about 1 year ago when I first got the car. Heads were machined down and checked for flatness before and after. Guy at the machine shop said they weren't warped at all before and they only took off ~ .0005 to be sure it was a clean surface. I hand polished the block itself with a 2S polishing wheel to remove all of the old gasket and crud. I'm an aerospace machinist by trade so I know I did it correctly and checked the flatness afterwards on the block itself as well. Had a mechanic from Subaru even come over and torque the head bolts and inspect the block and heads before it was reassembled. Said everything looked great and couldn't see any issues.

 

[SubaDrew87]

The very first thing to do is pressure test the system. Will it hold 15 PSI. If it won't, find the leak. If you are lucky, its a hose. If you are unlucky its a cracked block or engine gasket.

I'm pressure testing the system by letting the car heat up and feeling the tube. Before the head gasket change it was holding pressure... now it's not. Seems like most of it is dripping into the exhaust and out of the oil cooler. Could the oil cooler be another source of the issue?

Also are the Fel-"pro" MLS gaskets known for having defects? The other gasket I had to return because there was a crimp and was bowed so much that it would have definitely caused a leak.

 

[Easy Fixer]

You're over thinking and over fixing this problem. "It could be" isn't going to fix the problem. Positively diagnosing the problem will fix it. Borrow a Coolant pressure tester from an auto parts store. The MLS gaskets are fine. Good luck!