1995 325i overheated

Hey guys, a sad note brings me here. For the past year I have been sick of my car overheating at the wierdest of times. First time it overheated (went into red and the light came on) I have no clue what caused it, probably a bad fan clutch, it seemed to run ok after that until it once again started overheating. Within a year I have changed the following: fan clutch, thermostat, thermostat cover, fan blades, waterpump and of course got new coolant in. Within this week I've noticed that after standing at idle for a while, the temp would start slowly going up, upon turning the AC on, it would come right down (I figured the emergency electrical fan wasn't working for some reason). The check coolant level warning would sometimes come up on the OBC after I shut the engine off, this morning I checked the coolant level and it was maybe 3 inches above the "Full" mark. Since the car was praked on an decline, I just thought the coolant came down to the expansion tank and it should be ok.

Later on today I had to drive through 2 hours or more of stop and go traffic. It wasn't too hot out (maybe in the 90s), I had the windows down, I noticed the temp started slowly crawling up, I turned the AC on and it returned to normal, I think I just kept the AC on for the most part.

Then I parked the car, came back to it maybe an hour later and headed home. I was doing around 60 mph on the high way for around 10 minutes and everything was fine. I had to cross a bridge and as I approached the On-Ramp, i got stuck in a traffic jam which lasted for probably 5 minutes. As soon as I aslowed down I smelled the coolant. Within a minute or two the temp gauge started crawling again, I put the AC on but its not helping, I truned the heat up all the way, still crawling up. Got on the bridge and while accelerating towards the middle high point of it, I noticed that there was not hot air coming out of the vents, it was same temperature as the outside (engine block is dry of coolant at this point). I started going downhill on the bridge, put her in neutral and hoped the temp would come down, it didn't, it went into the red and the light came on. There is absolutely no stopping on the bridge so I had to keep going.

I slowed down for the tolls to maybe 10 miles an hour and went off an off-ramp maybe 300 away from the tolls (the light is still on). Drove probably another 3-5 long city blocks at around 30 mph and stopped. Shut the engine off and a little bit of steam was coming out of the hood. I got 2 galons of water, poured it on the engine, unscrewed the expansion tank cap and of course it was all dry, I poured some water in there, actually probably around a gallong and a half if not more. Got in the car, checked the temp, it was at the center mark (normal). Begged her to start, she cranked right up and fired right away. I drove home (probably another 5-10 long city blocks), it was still at the center mark. Checked it out and found a few things. The fan blades were all gone (how?, why?, where?, when?, I have not a clue), the little hose from the top of the radiator going to the bleed screw was disconected at the bleed screw and was hanging down between the radiator and the fan.

Maybe the hose came off because there was too much pressure in the system and broke all the fan blades. Maybe the blades magically disapeared overheating the system and blowing the hose off. I have not a clue. When I was pouring water over the engine, I checked the oil and it didn't look white milky or anything close to that, it just smelled burnt a little (mobil one synthetic, not even 3k on it).

Guys, help me out, I don't know what to do. What are the chances of the head being warped or the head gasket being blown and is there a way to check for either or both without having touched half of the engine with my hands? I do most of the work myself so I am not sure what to do. Should I even replace the blades, the hose, thermostat and all that stuff if the head is blown. I can't afford a new head or even just paying a mechanic to tear the engine apart to check out the condition of it.

What do you all think? Any help at all is appreciated. Sorry for the long post, I just wanted to be as clear and detailed as possible. Thanks in advance.

Reply to
andrey.ivannikov
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Check the obvious first, like is there water in your oil, or oil in the coolant (maybe harder to discern). Pull out the spark plugs. Only then you wil know if you're head/gasket is a goner. Perhaps they're still good.

I have to say pouring water on your engine while overheating may not be the best idea.

Could it be that your radiator is plugged to begin with?

Anyway, I'm sure there are more experienced BMW guys here who can comment.

Reply to
bimbim

It didn't look like there was water in the oil, but I guess I will need to change the oil to find this out for sure. If I pull out the spark plugs, what would I look for to check if the head is gone?

Could be the rad, I have no clue, I really don't know with this car's cooling system, its like its filled with mystical creaters who just do random stuff.

BTW, I forgot to mention a few things. I noticed that right before I stopped the engine was racing high and low, the rpms were going from like 250 to maybe 1k in neutral. Also, that hose that came off, I had a problem with it before, it got loose and the fan blades took off a good part of it, leaving a little hole for the coolant to escape through. I changed the hose but there was a factory clamp (ironically on the same side that it came off this time) that of course I could not use, the only dealer that is any close to me is a toyota dealer, so I just got one of those adjustable hose clamps from them. Maybe that thing wasn't tight enough, but why did it come off just now?

One more thing, thinking about it, I might have gone aquarter to half a mile with the temp in the red with speeds ranging from 50mph to 15 at the tolls to about 30 after them until I stopped.

Anyhow, thanks for the response, I appreciate it, I hope the head/gasket isok or at least the head.

Reply to
andrey.ivannikov

Pouring water on a hot engine is extremely ill advised... Do a pressure test of the coolant system to see if there are any leaks, and if so, where. Jim

Reply to
Jim

It sounds to me like you over heat when there is little airflow, and the heat goes back to normal when airflow returns.

This points me to the fan clutch. Of course, finding all of the fan blades fallen off is never a good sign, and this recently happened to my car. The new fan will set you back just under $60 at the dealership, and it is easy for you to replace. The fan clutch seems to not be working for you though, and this is a bit more difficult to address.

Another known issue is the impeller on the water pump itself, the impeller blades are plastic and they tent to disintegrate over time. This can contribute to poor circulation of coolant. A sign of impeller trouble is that the car gets hot, but the heater (cabin heater) performance is low.

One thing to be aware of is that you managed to get the Overheat Light to come on, this is a warning that you may have damaged the head. The head has a water galley (passage) that is right next to the exaust valves, and the galley walls are known to crack in the area adjacent to one of the #3 Exhaust Valve seats. The head can crack in other areas, but the one I suggested is among the more common places. There are two exhaust valves for each piston, but one of the two #3 valves has the thinnest walls where the water galleys are.

Reply to
J Strickland

My fan blades mysteriously disapear all the time. When I got the car it was missing 1 blade, I replaced that, then I noticed it is yet again missing 1 fan blade, replaced it again and now it has none what so ever. As I stated before, the fan clutch should be ok since I personally put a brand new one in less then a year ago and it was working because after standing at idle for a while, the car would sound like a truck once I move because of all the air being sucked in. Recently I haven't heard that sound though, but that is because I've had music constantly playing and just wouldn't hear it over the music so the fan clutch could have broke down.

I know of those plastic blades, when I was replacing the water pump, I went to the dealer and before paying for one I checked the blades, plastic. Gave the pump back and got one online with metal impeller.

Well, I hope it didn't crack or I guess I am done. Do you know how the car will behave if this happends? Will it get gasses in the cooling system forming a bubble and once again causing it to overheat or are there other symptoms?

Thanks for the response, I'll get the fan online, I bought one a few months back for 36 dollars at the dealer and when today he wanted to charge me a full 50, I said no. Got home and a fan blade can be had for $23 online so I'd rather get it there.

I'll keep you guys posted on how it goes. More replys and opinions are very welcome.

Reply to
andrey.ivannikov

About how much does the pressure test go for these days?

Reply to
andrey.ivannikov

I changed the expansion tank, put everything together except for the engine fan and bled the system. I then left the car running for almost

20 minutes in the drive way at idle (supposably perfect conditions for overheating) and not once did the gauge go above the center mark. the radiator warms up, the electrical fan comes on, cools it down and no problems what so ever. I took it out around the block and no signs again, took it out to get some groceries and once again, she ran perfectly fine even without the engine fan (91 degrees F out that day). I am guessing the head was cracked already when I got it, thats why I get the "Check coolant level" warnings out of nowhere and sometimes overheat out of nowhere. Also maybe the radiator thermostat for the axulary fan got stuck and when I accidentally droped it, the contacts got unstuck (because it is obviously working now).

I can't afford a new head right now so I guess what I will do is put in the engine fan and just bleed the system every 2 weeks or so. I think to me it could be one of those leaks that are not worth fixing because fluid can be added for much cheaper.

Thanks for all your replys guys.

Reply to
andrey.ivannikov

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