Coolant system problem

[villajo]

Hi
I am new to the forum...I own a 535 ia '92 model

This week my mechanic (not a BMW specialist) found a crack in the hose between the thermostat and the water pump that was the reason of the leakage of coolant from the system. He replaced it and used water to replace the coolant missing, around 2 gallons. This was done 2 days ago.
I haven't used the car to much, but anyway this morning after coming from an errand and after parking the car at home I noticed a hissing noise that after opening the motor cover found out that came from the coolant reservoir where the water/ coolant was boiling. I used almost 1 more gallon of water to come to the level indicator on the coolant reservoir; this done after the system was cool.
I haven't talked with the mechanic yet but most probably my understanding is that this is the result of using water only instead of the mix 50% water/coolant...anyway will gladly accept any suggestion on how to fix the problem...i.e change the thermostat, or other if necessary…

Tks

Note: the gauge indicator in the front panel never went over half mark where it is normally set.

[homer+vat]

See this post, it worked for me!
http://www.bimmer.info/forum/showthread.php?p=66163#post66163

Andy

[Kalevera]

Two problems: 1) the mechanic's put water into the system, which doesn't quite work the same way as coolant does, 2) the mechanic probably didn't bleed the car correctly when he refilled the system. None of the following applies given that right now you've got water versus coolant in the system (but I wrote it before I really thought about the problem...and when you replace the coolant, some of it might help you out). Water obviously boils at lesser temperatures than does coolant (or pressurized coolant, for that matter). So I'd suggest getting that switched out right away with some BMW cool blue (read below).

Are you SURE the temperature gauge didn't go above the 1/2 mark when you noticed the hissing sound? air sitting around the thermostat that's keeping it from opening. First, you could try bleeding the system (open the bleeder screw and let the coolant flow out until you get a steady stream without bubbles in it). However, if you want to save yourself a lot of time, the quick and dirty way to fix this is to remove the thermostat, drill a 1/8" or 1/16" hole at the 12'o position, and then reinstall it. Then, when you bleed the system, the air can move past the tstat and get bled out when you open the screw.

Also, water could be used temporarily, but you really should pick up some BMW Cool Blue (the OEM coolant available from a dealer) and make a 50/50 mix with distilled water.

That hose, BTW, is known to explode.

best, whit

[villajo]

See this post, it worked for me!
http://www.bimmer.info/forum/showthread.php?p=66163#post66163

Andy

Tks

there is a lot of info on that post that relates to my problem: ttast, bleeding,cooling mix replacement method.

Hope it will help me in solving it.

rgds

[Javier]

Javier

[villajo]

Two problems: 1) the mechanic's put water into the system, which doesn't quite work the same way as coolant does, 2) the mechanic probably didn't bleed the car correctly when he refilled the system. None of the following applies given that right now you've got water versus coolant in the system (but I wrote it before I really thought about the problem...and when you replace the coolant, some of it might help you out). Water obviously boils at lesser temperatures than does coolant (or pressurized coolant, for that matter). So I'd suggest getting that switched out right away with some BMW cool blue (read below).

Are you SURE the temperature gauge didn't go above the 1/2 mark when you noticed the hissing sound? air sitting around the thermostat that's keeping it from opening. First, you could try bleeding the system (open the bleeder screw and let the coolant flow out until you get a steady stream without bubbles in it). However, if you want to save yourself a lot of time, the quick and dirty way to fix this is to remove the thermostat, drill a 1/8" or 1/16" hole at the 12'o position, and then reinstall it. Then, when you bleed the system, the air can move past the tstat and get bled out when you open the screw.

Also, water could be used temporarily, but you really should pick up some BMW Cool Blue (the OEM coolant available from a dealer) and make a 50/50 mix with distilled water.

That hose, BTW, is known to explode.

best, whit

Tks Lowell
I can't really assure that the gauge didn't go over the half mark as when I notticed the hissing sound I've already turn off the engine. I had been checking it while driving and didn't see any indication on the contrary.

On rgds of replacing coolant with water, this was done temporarily and beeing no mechanic myself (and I can comment: very far of it, my knowlegde is scarce) he assure me that after the bleeding there were no air boubles.

Seems that the right direction could be replacing the whole coolant system with the right mixture and chcking the ttast.

rgds

[genphreak]

In the event of any concerns, first thing to do is check to see if you have any air in the system by taking off the resovoir cap once the engine has been off for a while and is cool (burns don't help anyone troubleshoot). Open the bleed screw on the thermostat housing. Watch for air (no coolant) coming out and or any bubbles in the coolant. There may be a few. Think of how much air could be up in that housing- any more than a few inches cubed of air and the engine has a serious air block (would only take 5 secs or so to come out) - fix before running the engine again.

An air block in the thermostat housing will come not being bled enough after being opened (obviously a possibility) and water leaking out (hot check required).

If you bleed the system and it heats up beyond the half way mark, let it cool down and check again for air at the bleed screw. The remove the thermostat housing to check the orientation of the thermostat as those that don't know better can get them round the wrong way with the spring inside the housing (not the housing cover). Your mechanic is VERY unlikely to do this. Also check for the little arrow on it to be facing up- many screw this up. I suggest drilling a 1-2mm hole dia. hole (very carefully or you'll be buyign a new thermostat- perfect operation is critical), in it next to the arrow to help you bleed the wretched thing. Its a known modification, well documented in the forums. In my experience, use the degree thermostats.

There is not very much water below the level of the thermostat, other than that in the resovoir. Sounds right that if you change the hose you would need to replace about 2G of of coolant, but taht it would only come from the radiator, (it wouldn't come out of the block as the hose fitting are all up high on the block).

Rergardless, your mechanic has filled it up with water afterwards (which is the right thing to do in the absence of BMW coolant, many would jam they're preferred (ie discounted tinted green water) in there and charge you for it...

Looks like you should go get a few bottles of cool blue and do some checking and even take it back. Might be easier to look after it yourself though. You just need a selection of 6, 8 and 10mm spanners and mini sockets (with extensions). If tightering any readiator hoses be careful- the radiator necks are plastic and break easily- be sure to check hoses and renew bad ones instead of over-tightening old ones, always, always!!!

;) GP

PS, once it is togther stop after you've gone a little way testing and be sure to look for any leaks in the hoses below water level of the thermostat. I wait for teh engine to warm up enough to evaporate any water i had spilt over it. These if left will introduce air into the system every time water leaks out, eventually giving you an air block in the thermostat housing that will need bleeding to prevent the cylinder head overheating. You really don't want this happening- just think of the heat and pressure changes the cooling system goes through every time you drive the car anywhere...

[villajo]

In the event of any concerns, first thing to do is check to see if you have any air in the system by taking off the resovoir cap once the engine has been off for a while and is cool (burns don't help anyone troubleshoot). Open the bleed screw on the thermostat housing. Watch for air (no coolant) coming out and or any bubbles in the coolant. There may be a few. Think of how much air could be up in that housing- any more than a few inches cubed of air and the engine has a serious air block (would only take 5 secs or so to come out) - fix before running the engine again.

An air block in the thermostat housing will come not being bled enough after being opened (obviously a possibility) and water leaking out (hot check required).

If you bleed the system and it heats up beyond the half way mark, let it cool down and check again for air at the bleed screw. The remove the thermostat housing to check the orientation of the thermostat as those that don't know better can get them round the wrong way with the spring inside the housing (not the housing cover). Your mechanic is VERY unlikely to do this. Also check for the little arrow on it to be facing up- many screw this up. I suggest drilling a 1-2mm hole dia. hole (very carefully or you'll be buyign a new thermostat- perfect operation is critical), in it next to the arrow to help you bleed the wretched thing. Its a known modification, well documented in the forums. In my experience, use the degree thermostats.

There is not very much water below the level of the thermostat, other than that in the resovoir. Sounds right that if you change the hose you would need to replace about 2G of of coolant, but taht it would only come from the radiator, (it wouldn't come out of the block as the hose fitting are all up high on the block).

Rergardless, your mechanic has filled it up with water afterwards (which is the right thing to do in the absence of BMW coolant, many would jam they're preferred (ie discounted tinted green water) in there and charge you for it...

Looks like you should go get a few bottles of cool blue and do some checking and even take it back. Might be easier to look after it yourself though. You just need a selection of 6, 8 and 10mm spanners and mini sockets (with extensions). If tightering any readiator hoses be careful- the radiator necks are plastic and break easily- be sure to check hoses and renew bad ones instead of over-tightening old ones, always, always!!!

;) GP

PS, once it is togther stop after you've gone a little way testing and be sure to look for any leaks in the hoses below water level of the thermostat. I wait for teh engine to warm up enough to evaporate any water i had spilt over it. These if left will introduce air into the system every time water leaks out, eventually giving you an air block in the thermostat housing that will need bleeding to prevent the cylinder head overheating. You really don't want this happening- just think of the heat and pressure changes the cooling system goes through every time you drive the car anywhere...

Tks GP

On your detailed advise and procedures, specially on the ttast side. They will be very helpful on taking it up further with the mechanic; I again admit that this is not my strong point by far. Plus I trust his work ethics.

Again tks for your advise

[genphreak]

Tks GP On your detailed advise and procedures, specially on the ttast side. They will be very helpful on taking it up further with the mechanic; I again admit that this is not my strong point by far. Plus I trust his work ethics. Again tks for your advise
No trouble friend, perhaps this will help some others too as it is pretty much how I go about it. It is easy to make mistakes and overheat the engine too (or at least worry about doing so)... I bet your mech was doing the right thing, just didn't bleed it right or got the wrong thermostat or something. The bleeding may take several goes... witha hle in the thermostat perhaps only two. If they are familiar with these motors you should be fine. If they aren't **don't** go back.. it isn't worth you risking a warped cylinder head whilst they learn what not to do... and you are probably not in a position to educate them about it right now, they'd probably mistake what you said and blame you should it go wrong.. I guess that's why most of us on these boards prefer looking after it ourselves, as we have a community to build knowledge with and help us from avoiding costly mistakes. :) GP

[GS535i]

You should ask the question as to why that 'U' shaped hose failed:was it due to fatigue/old age/- or did it die a premature death due to something else still present - and that will strike again.
I had a similar failure on my 535i. The hose was temporarily replaced with a similar section chopped from a ford truck part and refilled with water, leaving the rad cap loose - a bandaid to get me home. It boiled over again at the house, so there was another problem. While the thermostat was replaced along with the correct hose, it appeared that the primary problem was swelling of the O-rings on the rad cap. This blocked the small rad return line, even with a loose cap.
Try a new cap along with a thermostat.
BTW, no fluid has as high a specific heat as pure water - it is the best coolant known; however, it doesn't handle winter and corrosion as well as a 50/50 antifreeze mix. You are fine with water on the short term.

[632 Regal]

You are fine with water on the short term..

[villajo]

You should ask the question as to why that 'U' shaped hose failed:was it due to fatigue/old age/- or did it die a premature death due to something else still present - and that will strike again.
I had a similar failure on my 535i. The hose was temporarily replaced with a similar section chopped from a ford truck part and refilled with water, leaving the rad cap loose - a bandaid to get me home. It boiled over again at the house, so there was another problem. While the thermostat was replaced along with the correct hose, it appeared that the primary problem was swelling of the O-rings on the rad cap. This blocked the small rad return line, even with a loose cap.
Try a new cap along with a thermostat.
BTW, no fluid has as high a specific heat as pure water - it is the best coolant known; however, it doesn't handle winter and corrosion as well as a 50/50 antifreeze mix. You are fine with water on the short term.

Dinan/Bilstein

Tks for the advice coming from your own experience …now it also puts the problem of the hose as maybe an effect and not the cause against what it was my understanding.
Yes the use of water was a temporarily solution after the replacement of the damaged hose.
But it lead me also to post my concern on regards as not being the proper coolant mix for the engine and thus it could come back and catch me with another related problem.

rgds

[Kalevera]

Villajo - I highly doubt there's a problem with the cooling system -- it just needs coolant. Remember that "normal operating temperature" with a standard thermostat is about 80 degrees celsius (see http://www.nmia.com/~dgnrg/tempgage.htm), so water will steam a lot at that temp...and if air was left in the system and wasn't bled out by the mechanic, then the water could've potentially sat there and heated up even more - boiled - hence your hissing sound.

So, get some actual BMW coolant and distilled water (or mercedes/zerex if you can't find the BMW stuff) and then see what happens.

Best, whit

[villajo]

At the end, at least I hope so, the problem laid in the cap of the water/coolant reservoir which was faulty and being no proper pressure applied it resulted in the boiling of the coolant mix. The car is still working with only water till it’s final that the problem was solved before changing it to the proper mix.
The cap, by the way, was the original since in bought the car in May ’92.

I would like this to express my tks to you people that sent your advices, posted your concerns and own experiences. Hope that mine could also be helpful in the future

rgds