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Manny
02-13-2000, 06:39 PM
Hi All,<p>Just thought I would share with you a disturbing experience..<p>A couple of weeks ago I replaced the thermostat on my 89 735iL becase it was not closing properly and seemed to take a long time to warm up. I thought I would use my bently to save myself some workshop costs...<br>All was well until I was pressure testing the cooling system and I discovered I had managed to crack the thermostat housing and coolant was leaking from the crack.<br>So... I sourced another housing, and figured I would replace the main hoses at the same time since there seemed to be a lot of buildup of scale in the hoses. I also got a new expansion tank because the old one was brown inside.<br>Everything went well although it was a bitch to bleed and coolant got everywhere.<br>My wife and I decided to go on a pre valentine/pre baby arrival weekend away. We went to a little town 200 miles away and all was fine with the car.<br>The next morning, after topping off the coolant level,We were coming back home and my wife noticed steam. We were in a volcanic area where steam rises from the sewage gratings so for a minute we ignored the possiblity that the car was steaming. However, I noticed the temperature gauge climbing so we pulled over on the side of the road.<br>Upon opening the bonnet I saw the top hose had popped off the radiator. I reattached it (I had bought my tools with me) and filled up with water. This time because the car was hot, the system would not bleed properly and the there was a huge air bubble somewhere that was preventing water circulation. I put the cap back on, drove about 3 miles to a service station and the hose popped off again.Two hours later, the car had cooled down sufficently to try beeeding it again. It would still not bleed. Coolant kept overflowing from the expansion tank and no amount of refilling would see water coming out of the bleed valve.<br>I rang up the nearest BMW shop who told me the head gasket was probably blown, and we would have to leave the car with them for a week. After this conversation and a lot of swearing, I looked at the resoivoir tank and it was empty, meaning the coolant had actually flowed to the motor. I filled it up, put the cap back on and tightened the top hose as much as possible. I noticed that the clamp had very little to clamp onto. The car seemed fine, so we drove to BMW dealer and they told me that there should be 3 inches of plastic tubing on the radiator for the hose to slip onto - not the 1 inch I had. They said a new radiator was required.<br>I took a punt and decided to drive the 200 miles home to get my mechanics opinion. We got home no problem with a constant eye on the temp gauge. My independant BMW mechanic said that this was a common problem and a new side tank for the radiator could be arranged. He has the car now and I will be without it for 1 day. In the meantime I have a 318i loaner which has wonderful steering compared to my 7 but the rest is yuk.<br>Moral of the story - Make sure when replacing the top hose that you tighten it as much as possible and that the tube has not perished.

lg
02-13-2000, 08:35 PM
this is the problem i'm having. i replaced the thermostat and bled the system so i think i did. i have no leaks at all that are visual. every other day or so, it overheats, no water in oil? i just can't figure the dam thing out.<p><p><p><i>: Hi All,<p>: Just thought I would share with you a disturbing experience..<p>: A couple of weeks ago I replaced the thermostat on my 89 735iL becase it was not closing properly and seemed to take a long time to warm up. I thought I would use my bently to save myself some workshop costs...<br>: All was well until I was pressure testing the cooling system and I discovered I had managed to crack the thermostat housing and coolant was leaking from the crack.<br>: So... I sourced another housing, and figured I would replace the main hoses at the same time since there seemed to be a lot of buildup of scale in the hoses. I also got a new expansion tank because the old one was brown inside.<br>: Everything went well although it was a bitch to bleed and coolant got everywhere.<br>: My wife and I decided to go on a pre valentine/pre baby arrival weekend away. We went to a little town 200 miles away and all was fine with the car.<br>: The next morning, after topping off the coolant level,We were coming back home and my wife noticed steam. We were in a volcanic area where steam rises from the sewage gratings so for a minute we ignored the possiblity that the car was steaming. However, I noticed the temperature gauge climbing so we pulled over on the side of the road.<br>: Upon opening the bonnet I saw the top hose had popped off the radiator. I reattached it (I had bought my tools with me) and filled up with water. This time because the car was hot, the system would not bleed properly and the there was a huge air bubble somewhere that was preventing water circulation. I put the cap back on, drove about 3 miles to a service station and the hose popped off again.Two hours later, the car had cooled down sufficently to try beeeding it again. It would still not bleed. Coolant kept overflowing from the expansion tank and no amount of refilling would see water coming out of the bleed valve.<br>: I rang up the nearest BMW shop who told me the head gasket was probably blown, and we would have to leave the car with them for a week. After this conversation and a lot of swearing, I looked at the resoivoir tank and it was empty, meaning the coolant had actually flowed to the motor. I filled it up, put the cap back on and tightened the top hose as much as possible. I noticed that the clamp had very little to clamp onto. The car seemed fine, so we drove to BMW dealer and they told me that there should be 3 inches of plastic tubing on the radiator for the hose to slip onto - not the 1 inch I had. They said a new radiator was required.<br>: I took a punt and decided to drive the 200 miles home to get my mechanics opinion. We got home no problem with a constant eye on the temp gauge. My independant BMW mechanic said that this was a common problem and a new side tank for the radiator could be arranged. He has the car now and I will be without it for 1 day. In the meantime I have a 318i loaner which has wonderful steering compared to my 7 but the rest is yuk.<br>: Moral of the story - Make sure when replacing the top hose that you tighten it as much as possible and that the tube has not perished.<p></i>

sam
02-13-2000, 09:30 PM
Sorry to here that. I just had a small leak in my<br>radiator and all the shops around here wouldn't fix it :( $269 for a new 750il radiator from allbmwparts.com , but they were expedient and 1 hour labor to replace it AND bleed it, were worth the time and money. Mechanic says bimmers take 30 minutes to bleed and are a major pain in the ***.<br>

Scott Mc
02-14-2000, 12:15 PM
Regarding bleeding 750s. I never had to bleed mine because of the circulation tube between the water pump and expansion tank. I thought all 12 cyl motors had this type of water pump.

sam
02-14-2000, 06:24 PM
dunno but before the bleed there was no heat at all, after the bleed, heat was great. seems the air likes to hang out around the heater core :)<p><br><i>: Regarding bleeding 750s. I never had to bleed mine because of the circulation tube between the water pump and expansion tank. I thought all 12 cyl motors had this type of water pump.<p></i>

Gale Hawkins
02-14-2000, 09:48 PM
Sam as a good point on replace vs repair. My 82 733i had a short intake nipple when I got and finally 2 years later it got where the hose just would not stay on at all. The radiator shop tried the new cap solution but too many tabs broke off. For $200 they said they could get a new one. That was a no brainer in my case because that was only $15 more than the repair quote was for. The R/R was the same either way.<p><p><i>: Sorry to here that. I just had a small leak in my<br>: radiator and all the shops around here wouldn't fix it :( $269 for a new 750il radiator from allbmwparts.com , but they were expedient and 1 hour labor to replace it AND bleed it, were worth the time and money. Mechanic says bimmers take 30 minutes to bleed and are a major pain in the ***.<p></i>

Gilbert
02-15-2000, 07:18 PM
will crack off at the hose clamp if you tighten it too much. Then the other two inches are still in the new hose. If not tight enough it will pop off. They should not be made of plastic.<br>Good luck.<p><br><i>: Hi All,<p>: Just thought I would share with you a disturbing experience..<p>: A couple of weeks ago I replaced the thermostat on my 89 735iL becase it was not closing properly and seemed to take a long time to warm up. I thought I would use my bently to save myself some workshop costs...<br>: All was well until I was pressure testing the cooling system and I discovered I had managed to crack the thermostat housing and coolant was leaking from the crack.<br>: So... I sourced another housing, and figured I would replace the main hoses at the same time since there seemed to be a lot of buildup of scale in the hoses. I also got a new expansion tank because the old one was brown inside.<br>: Everything went well although it was a bitch to bleed and coolant got everywhere.<br>: My wife and I decided to go on a pre valentine/pre baby arrival weekend away. We went to a little town 200 miles away and all was fine with the car.<br>: The next morning, after topping off the coolant level,We were coming back home and my wife noticed steam. We were in a volcanic area where steam rises from the sewage gratings so for a minute we ignored the possiblity that the car was steaming. However, I noticed the temperature gauge climbing so we pulled over on the side of the road.<br>: Upon opening the bonnet I saw the top hose had popped off the radiator. I reattached it (I had bought my tools with me) and filled up with water. This time because the car was hot, the system would not bleed properly and the there was a huge air bubble somewhere that was preventing water circulation. I put the cap back on, drove about 3 miles to a service station and the hose popped off again.Two hours later, the car had cooled down sufficently to try beeeding it again. It would still not bleed. Coolant kept overflowing from the expansion tank and no amount of refilling would see water coming out of the bleed valve.<br>: I rang up the nearest BMW shop who told me the head gasket was probably blown, and we would have to leave the car with them for a week. After this conversation and a lot of swearing, I looked at the resoivoir tank and it was empty, meaning the coolant had actually flowed to the motor. I filled it up, put the cap back on and tightened the top hose as much as possible. I noticed that the clamp had very little to clamp onto. The car seemed fine, so we drove to BMW dealer and they told me that there should be 3 inches of plastic tubing on the radiator for the hose to slip onto - not the 1 inch I had. They said a new radiator was required.<br>: I took a punt and decided to drive the 200 miles home to get my mechanics opinion. We got home no problem with a constant eye on the temp gauge. My independant BMW mechanic said that this was a common problem and a new side tank for the radiator could be arranged. He has the car now and I will be without it for 1 day. In the meantime I have a 318i loaner which has wonderful steering compared to my 7 but the rest is yuk.<br>: Moral of the story - Make sure when replacing the top hose that you tighten it as much as possible and that the tube has not perished.<p></i>


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