Overheating/blown hose - how bad?

[griffincox]

Hey guys,

Sorry for the long post in advance.*

I am new guy to the forum. I was looking at 1989 325i in my area a few weeks back and missed out on it. Fast forward to more recently. I found a 1990 325is in Phoenix (I am from Denver). So I made plans to buy it and flew down this past weekend to pick it up. Few little things here and there, but pretty much original and in great shape with 175k miles. * I drove east into Albuquerque and it was winter condition and very cold. Engine was running way to cold. Figured the thermostat was stuck open. * So I found some cardboard and stuffed it in front of the radiator. It ran much warmer but not quite in the middle. * Good enough though. Drove it home 800 miles no problem. Parked it last night outside (0 degrees F) very cold. Started up this morning to wash it a bit and put it in storage for the week cause I am traveling. Drove it and it immediately started getting much hotter than it did the last 2 days and hundreds of miles and got above center and towards red quickly. I should have turned the heat on or stopped and removed the cardboard but I didn't. *Stupid I know. Anyway it got to the red for about 3-5 minutes and about 2 miles or less and a radiator hose burst (surprise). I shut it down shortly after washed it a bit and started it again (15-20 minutes had passed) and ran it for less than a minute to get it into storage. This whole time the temp outside is single digits. *

FYI, the car has a new timing belt, water pump and radiator in recently and also some head work done, but may have a missing or stuck thermo. *Been an AZ car it's whole life and probably never seen cold temps like it did the last 3 days.*


I have a few questions:
- why did it get so hot so fast today and it didn't the last two days? *I know the short answer is the cardboard blocked air and over heated it, but it's colder now than on the trip where it ran a little cool and below half on the temp gauge *and the cardboard is covering less than half the radiator. *Seems crazy it got so hot so fast which is kinda why I didn't stop. I figured no way it got that hot that fast. But I was wrong. What do you think, slower driving speeds, frozen coolant?

- how much damage do you think was done? *Obviously this is not good, but how bad is it for the engine? *Water pump? *

I already ordered a new thermostat. I guess I gotta get some new hoses too.*

Anything I should look for damage wise? *Anything else to replace? *Would the head or gasket be damaged by this?*

I appreciate the help. I feel so bad for the little car. *Hopefully i didn't hurt it too bad.*

[E30_fiend]

your thermostat could have frozen shut as well as your coolant thats in the motor probably isnt rated to freezing or colder temps. Most coolant available in the southern states with efficiently cool/warm down to like 25 degrees. anything less than that and the coolant cant do its job.

I personally think you should replace the hose, do a compression test and get some NEW ANTIFREEZE(lol) coolant in there and see where youre at.

If you can get it started and running warm but not hot, consider yourself lucky. You could have very possibly popped the head gasket.


Taylor

[jlevie]

My suspicion is that there was not enough (or no) antifreeze in the system and the cooling system froze. At those temps the cardboard in front of the radiator would not have resulted in the overheat, especially not that quickly.

The bad news is that running the engine in the red that long had probably damaged the head gasket and warped the head. Just hope that it didn't crack. If it were mine, I'd immediately drain the block (the radiator is probably already empty) and pull the head. It would then go to a machine shop to be checked for warp and cracks (with a pressure test). A 175k you might as well rebuild the head. I'd also replace the water pump, thermostat, all cooling system hoses, radiator, heater core, and expansion tank. All of those parts are suspect at this point.

[griffincox]

Thanks for the help already. I think the head was worked on recently (machined, new gasket, idk what else). The frozen coolant makes sense. Seems more obvious now. Think its worth new hose, thermo, and flush and at least give it a try without pulling it apart?

[Ceeker]

Don't pull anything yet, except maybe the thermostat. Check for coolant loss through the exhaust and possible coolant in the oil of course this is after the new hoses and coolant, therm is back in. If you have neither, count you horseshoes. Also run the car again, bleed the system and check for temp stability. also check to see if your fan clutch didn't pack it in. You will know by taking a magazine rolled up to the fan blade. if the car is warm/hot and you can stop the blade with the magazine then your fan clutch is toast. You should be able to freely stop it while cold.

if you have coolant loss through the exhaust or coolant in the oil; = bad news. tear the top end down and have the head checked, resurfaced if the head isn't cracked. and get all new parts when installing it since the head is out. while you're in there stuff.

[griffincox]

Okay guys. Thanks for all the help. I finally got back into town and had a chance to look. The hose that burst is Waterpump->Thermo. I have a new one on its ways from pelican. Hopefully get it replaced this weekend. I am going to replace the hose and thermo, flush/fill the cooling system and then start diagnosing. How long should I run the engine for to determine the potential issues? Should I drain the oil to inspect? Any tips are appreciated. I am sure I can find this by searching, but any recommendations on a type anti-freeze? 50/50 mix? Thanks again!

[Ceeker]

just run it up to operation temp. if you see the temp go over half observe to see if it continues to move higher. But before you do this; add the coolant with the bleeder open until you see flow. then shut it. run it. to temp and observe. Bleed system, look for any signs of leaking, white sweet smoke from the tailpipe (coolant burning) look for coolant in the oil after shut down. if everything seems ok...just keep eyes on it for a few days in case any changes happen.

[griffincox]

Here's an update with a few more questions. I drained the block and radiator, replaced the hose, thermostat, and t-stat gasket and then put 1 gallon of Prestone and about a half gallon of distilled water in the expansion tank before it wouldn't take any more. Started the car and ran it with heat on for about 10 min up to operating temp. By the time it got there, there was quite a bit of steam. I could not tell the source though. Could just be water from spill, wash, etc getting hot or could be a leak. It got to where the thermostat probably should have opened but the expansion tank didn't empty out like expected. The bleeder valve didn't release much air, just fluid. Radiator got hot. Oil looks clean, exhaust looked good. I called it a night. Any tips on how to better bleed the system. It's probably only about half full would be my guess (~1.5-1.75 gal). Any good way to find the source of the steam? Would coolant leaking out of vs into the head be just as common a sign of damage (aka steam). Thanks again!