Definitely wait to do the test before assuming the worst.

I wouldn't pay a shop to tear down an HR for a head gasket swap, you're already familliar with the engine swap procedure and it's almost literally the EXACT same on the V36 so I would go that route if it does end up being the HG.

When you have a chance you should drain the coolant and let it sit overnight then look for sediment either floating on the top or settled to the bottom. It's entirely possible the seller used a head gasket/block sealant in the coolant to mask a problem that existed.

If so then take them to court for the cost of an engine, imo any used dealership will go all wide-eyed when they're presented with legal obligations to appear in court. Take lots of photo's, do your research, you don't need to be a lawyer because the internet is full of free advice on how to sue someone and that's exactly what you would be doing. It's actually pretty cheap if you're doing your own legal research (your time and the cost of the clerk filing fee), when I got out of my 2012 ZL1 Camaro that blew up on the highway that's exactly what I did. I suspected they had used block sealant for a cracked block which later hydrolocked the engine and detonated on the highway (literally blew up the motor, fragments embedded in the firewall...) with zero warning.

I took a lot of pictures/video, filed with the clerk, summoned the Chevy dealership I bought it from for the cost $5000 which is the max you can sue for in small claims court. They ended up settling via lawyers out of court and buying the vehicle back for the exact cost I had into it.

If it's a private seller that's different but if you suspect foul play then no harm in testing the waters of legal option.

'Murica!

 

Will do and thanks! I'll post after I run the test

 

Test completed.

Let the car warm up a bit an ran the test

Came back negative for exhaust leaks in the coolant ☺

To confirm a working tester I went to the rear of the car and tested the exhaust and it turned yellow immediately

 

Sounds like air in the system. Vacuum fill time!

 

Picking up a Lisle one tommoro ☺

 

So new plan of attack

Full radiator flush

Coolant drain and refill

Oem rad cap and thermostat

Burping procedure done with Lisle refill kit

 

I'm really glad that wasn't the head gasket. You need to add a step onto your plan of attack, step 1 pressure test the cap and the entire system.

 

Ok great I'll add that as well

 

Question for you guys, so I decided to do more digging while waiting for oem parts to be delivered and I filled the radiator with distilled water because it's being flushed in a few days anyway. I let the car get to 195 degrees (monitored by my torque app) top hose wasn't really hot and also I could squeeze hose until both sides touched inside.

Thermostat? Coolant wasn't at the right level?

 

More notes, was tinkering with the car after work and this is what I've gathered

Upon startup I could hear a clicking noise very audibly and it went away after a minute (I'm assuming this might be the water pump because it was on the passenger side)

I let the car idle until it hit 203 on my torque app and fans kicked on.

Upper hose was hot and lower was cold so I'm assuming thermostat is opening.

Car maintained Temps at around 215 until I decided to back out of my driveway.

Temps started to rise, so it seems it's only starting to overheat once I start moving.

Once Temps hit 220 I shut the car down, upon shutdown I got the usual overflow tank bubbling and seconds later the usual leak from the overflow tank releasing extra coolant.

I'm thinking the rad cap I bought wasn't a good one so I'll be heading back to store tomorrow to get another and perform more tests.

I'll keep the thread updated, hopefully this can help someone in the future.

 

Update!

OK I haven't been able to get my hands on a pressure tester BUT I decided to do some more testing and this is what I've learned.

OK usually after letting my car idle for 20 mins and turning it off results in violent bubbling and coolant spilling from the coolant overflow.

This time it didn't overflow because I had the Lisle funnel attached to bleed any air out of the system. No bubbling either.

So I'm thinking my month of thermostat is bad so I grabbed another one and I'll confirm if it's bad once the car cools off and I can remove the funnel

Can anyone confirm my logic? I'm thinking it's just the cap because after removing the cap no more bubbling or overflow leaks happened.

 

The thermostat would fail in open position by design. The cap certainly could be the problem. The cap introduces ~15psi of pressure to the cooling system and this allows your coolant (water) to reach 3 degrees above 212° for every psi of pressure. A weak cap is essentially a leak in the system if the spring isn't holding the pressure and can lead to boilover.

 

And I'm here to confirm after driving the car for a bit with a new thermostat and coming home there was no overheating and no bubbling. Gonna drive it a bit more to confirm but things are looking good ☺

 

And we are back.....

With the same issues, three rad caps later lol.

I'm thinking it's the thermostat at this point or maybe something major?

Question for you guys, I decided to bleed my system again and noticed something. While using the lisle funnel bubbles would start to appear around 4krpm. Is this normal? No bubbles at anything below 4k while revving. This has become quite tricky and a bit bothersome.

 

Have you used a coolant pressure tester on your car yet? It sounds like you are getting air in the system and if the system has air in it and is not completely sealed your boiling point will be a lot lower. Rent a pressure tester at a local auto parts store and see if it bleeds down over time.