Blown Head Gasket? Or something else....? Please help

[ALo615]

Ok, let me start by saying that this forum has definitely helped me diagnose and fix problems with my car numerous times, but this is my first time actually posting a thread.

I currently have an 03 530i with about 176k miles. About 2 weeks ago i was driving on my lunch break and as i was pulling into a parking lot i heard a loud "thud" followed by an explosion of coolant from under the hood. I immediately pulled into a parking space and shut the car off (total of about 30 seconds). The temp gauge was reading dead-center, no other issues were noted and there was no warning signs. I had the car towed to a friends shop and noticed right away that i had blown out the side panel on the radiator. Also, somehow my fan and temp sensor had been unplugged (i suspect foul play there...) My friend JB Welded the hole in the panel just to do a quick pressure test and make sure i hadn't popped a head gasket before i ordered a new radiator. Everything seemed fine (as i t could be anyway) no leaks, no smoke, no knocking, and the car was still making heat. I called a junk yard and got a replacement radiator only to find that the little "L" shaped connector joint was broken. so i ordered a new one and replaced that too. Once everything was put back together we filled the radiator with coolant and started it up, only to find a massive leak coming from the L shaped connector thing. We tried to let it warm up, hoping it would swell the seal but it never did. However, NOW the car is not registering temperature (needle stays dead center) and it will not blow heat! I had a pressure test done and the fluid didn't move a bit so im assuming that's a fail. But im curious whether or not it actually IS a blown head gasket, or if it could possibly be something else? We suspected that the thermostat was stuck closed and that's what originally caused the pressure build up that lead to the radiator blowing open. But i don't know now.

Any ideas? suggestions? or tests that i could maybe run to double check the head gasket before i send my baby away to scrap-yard heaven?

[Pelican Parts]

Hello and welcome to the forum! When you brought it the car to your friend's shop and had it diagnosed, what codes came up? These should give you a definitive answer as to where the exact issue is.

[ALo615]

Hello and welcome to the forum! When you brought it the car to your friend's shop and had it diagnosed, what codes came up? These should give you a definitive answer as to where the exact issue is.

I guess i probably shouldn't have said "shop", it's actually my friends work. He works on heavy equipment, some truck repairs, etc. for a property maintenance company. But his shop is equipped with a lift and everything we need so that's why i had it towed there. Unfortunately, i do not have the BMW code reader equipment.

[geargrinder]

If transpired as you describe, then extremely unlikely the HG blew. Nothing you're describing would suggest that. I suspect the car is fine.

If the T-stat was stuck you'd have blown the motor up not the radiator... The radiator has a pressure cap that should vent overpressure so - either somebody effed around and put a nonventing or high pressure cap on, or, more likely, BMW radiators just suck.

No heat like this usually means you haven't bled fully / properly. It's a bit tricky until you know the tricks, even if your bud is a great mechanic, if he's not a bmw guy he won't know this.

Since you found some shenanigans already... Check the exp tank cap. Did you note if the rad that blew out was original or some aftermarket thing? Not that real factory old ones won't crack and leak tho...

When you say temp sensor was disconnected, which one do you mean? These cars have multiple water temp sensors, in a late car like yours the one in the rad hose feeds the DME which then controls the electric fan. It maybe the PO had trouble with the fan running all the time and so disconnected both and just was relying on the mechanical fan (not great idea).

When you say temp doesn't register - have you tried using the secret cluster functions to display KTMP? That should give you numeric display of actual coolant temp at the engine.

I suspect you're ok but just may have some more work to do...

Search and read up on proper bleed technique. Then run the KTMP display as you warm it up. The Hardline you mention should have O-rings, I am guessing you just had an install error, maybe the orings slipped off or the old o-ring stuck inside the sockets... Could be it needs an electric fan and or rad temp sensor and that's why they were disconnected. Scan for codes for sure but I bet it gives you a bunch of errors for fan and coolant sensor being disconnected.

[ALo615]

Thank you! I will look into that.

I did have another friend of mine scan the codes yesterday, according to what he said - BMWs throw a special code for coolant in the combustion chamber and my car is throwing that exact code within 15 seconds of re-start after clearing codes / sitting for 24 hours. So im guessing that it indeed looks like the head gasket. Unless, that code could be thrown for something else... but i doubt it.

[geargrinder]

according to what he said - BMWs throw a special code for coolant in the combustion chamber

Possibilities:

1. This person is not actually your friend.
2. This person has access to laboratory grade psychoactives.
3. Your car and your friend has secretly been sent here from the future and contains Future Alien Technology.

[geargrinder]

Btw realized this thread is totally in the wrong spot.

Ask a mod to move it.

You havent written an informative post on a "common problem" or "DIY". You just have a problem.

[ALo615]

Btw realized this thread is totally in the wrong spot.

Ask a mod to move it.

You havent written an informative post on a "common problem" or "DIY". You just have a problem.

Gotcha. As i stated before, new here.... but will do. Thanks for the help.

[geargrinder]

You'll probably get better answers if it gets.towed to proper spot btw.