5-Series (E12,E28, E34, E39, E60)Chat relating to the BMW 5-Series of all generations. Specific models include: BMW 518, BMW 520, BMW 520i, BMW 530i, BMW 528i, BMW 530i, BMW 518i, BMW 524d, BMW 525i, BMW 525e, BMW 528e, BMW 540i, BMW 535i, BMW 520d, BMW 525td, BMW 525d, BMW 530d, BMW 525i/xi, BMW 530i/xi. (BMW 5-Series Forum)
Hey all I am new to forums and after intensive search I came up empty and hope you all can help me with my problem.
I have a 86 535i e28 BMW and it has been overheating like crazy, I started off with replacing the thermostat, then replaced the fan clutch, then replaced water pump, then replaced thermostat and housing this time, still overheating, replaced radiator, replaced dashboard cluster and the IS board as well. Also replaced both temp sensors on the side of the radiator as well. It overheats whether I am at idle or driving down the road or highway. I have also replaced and bled the system three times and so now I am just plain frustrated! Any help on this pain in the butt issue would be great! Will welcome any ideas or input
Well I bought it last year and prior to that I do not know what wasndone to it, I know that I replaced the fuel injectors with 19lbs injectors and the work that I already put down was all the work that I have done to it but I was told that the oil was changed and the change oil light always stayed on and it needed to be fixed, I found out what is was through this board :0) and changed it. How do I check the jacket around the block? Would there be a block somewhere through there? This is my first BMW and I love it and am trying to restore it at the same time, would this also account for the temp gauge bouncing around? Like it will move back forth from semi cool to hot then to overheating slighty To then jump close to the red and then back down again? And also I have tried to turn the heater on full blast and it does nothing to the engine it at all per the temp gauge, could it possibly be a sensor? Sorry for the long post, I am trying to give as much info as possible on my issue that is seriously chalking my hide
Sometimes ... it's more than one duck.
■ If you have a pocket of air trapped behind the thermostat it won't usually open, thus preventing the water from flowing correctly. If you have a pocket of air at the water pump it will cavitate, and water won't flow. If you have sludge or mineral deposits (you DO use distilled water, right?) they'll build up and act like restrictive insulation and you can overheat, even if water flows. If you have an old flimsy lower hose it can sometimes collapse, preventing the water from flowing.
So, as an old fart I usually drill a couple 3/16 holes in the thermostat before I install it. This lets the air escape right on thru, and it also allow a little water past so the thermostat acclimates immediately.
You know how the temp gauge bounces around? That's pockets of air mixed in the water. Mine used to do that. With the new and holey thermostat it just climbs to 1/3, and stays there. My advice? Trust nothing, check everything.
Pull the thermostat and put it in a pot on the stove, with a candy thermometer. Make sure it opens at the right temperature. While you're doing this put the housing back on, add some coolant system flush, and see how much crapola comes out. While you're doing that, check the fan and the fan clutch. Does it actually work and spin the fan, is there a lot of air rushing thru when you first start it and again when it gets hot. When you changed the temp sensors on the radiator did you check to see if they work, does that front fan really work, and does it work like a two speed fan? Did you make sure there's a clear air path, from the front of the car, thru the AC and water radiators, and out? Did you check the hoses, make sure they are fit functional not pinched or dented and they're routed correctly, if there is a bypass hose make sure it's not clogged with goo, and make sure the overflow tank is half full *all the time* until this is working properly.
Gidgaf, thanks for the help I will do all that as soon as I can, one question though, I just bought allnthese replacement parts, what arenthe odds that the new part would go bad as soon as I put it in? Well I just use 50/50 antifreeze which from the sound of things that is not a good thing? So what should I use instead? Or should I use just distiller water only and maybe add some water wetter to it?
Wanzzilla, there's not a lot to go wrong, especially if you check up on things. Did you check the thermostat on the stove? It should still be as good as that. Unless something bad happened to new hoses and they were installed correctly and they don't leak, they're still good. IF the water pump works AND the thermostat works AND the radiator is clean AND the hoses are good AND it's full of water AND the fans work AND the fuel/air mixture is right there should be no reason to overheat. EVER.
Did you ever check to male sure the fans work? My engine mounted fan goes VROOM! for a minute in the morning, and when it's idling I can hear it on occasion, starting up and shutting down. I never checked that my sensors actually started my electric, (I am soon, now!) but I do know the fan works and that the sensors work. Di you ever put your hand on the radiator and all the hoses to see if it was actually getting warm? Did you double check the reservoir level?
50/50 antifreeze is not bad. It ain't the best, but it's almost always good enough. I live in Hell-A, where where we've had a couple of the coldest nights for quite a while: down to 44 degrees at my house. THAT mean 35% antifreeze works the best for me, as far as heat transfer and aluminum protection. Read the label on your water wetter product- some of them make a big deal out of a couple degrees .
A good engineer/ mechanic/ programmer quote: the first 90% of the work takes the first 90% of your time and money. The final 10% takes the other 90%. Fix the big and easy stuff first! Did you check the temp sensor ...
Sorry for the long delay, but I live in Texas and my car was in California when this happened and I had to come back to Texas, so I had to go through a friend to another mechanic to talk to him to tell him what I had done and what the problem was, well as it turned out it was two fold, the water jackets were somewhat clogged up and the thermostat was bad, which is crazy because that was the third one I put in. I think I just have bad luck with those things LOL, anyways she is back up and running and I wanted to thank everyone for there great imput and possible ideas of what it could have been and what to look for. Thanks a lot everyone!!
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