Hi,
Anyone else had a problem with an E46 radiator like this :
Requires considerable topups of coolant for a couple of weeks No sign of any leak Finally realised ( after a tip off from a chap who had taken one apart ) that the radiator had severely deformed and expanded - mostly at the bottom into a bowed shape - see jpg :
Steve
PS. The picture is of the bottom of the rad and you cant see this until you've crawled underneath and removed the plastic splash guard.
This sounds like more of a cooling system overpressure fault. Some E34
5-series had a recall for this as the rads were blowing the header tank I believe. May be worth checking out with a main dealer to see if there any E46-specific recalls. I suppose you've already had a check done for a failing head gasket? cheers, JB
Bmw wont admit anything but a web search suggests there were problems in the USA. Their response to any technical query is allways "Take it to a dealer and pay them ( > 120 quid an hour ) to diagnose and fix it. As to the head gasket, well I doubt it, and even if it was, surely the system is supposed to "fail safe" : The cooland is perfect ( ie. water and antifreeze - no oil ), the oil contains no coolant, the temp gauge has never gone over normal. Engine has allways run OK. I replaced the cap at the same time as the rad and am hoping it doesnt happen again.
Why post a question if you don't want to act on advice?
It is worth checking the head gasket out and a simple gas test of the coolant can be done anywhere. I would have thought most people can check for pressure build up too.
I would also talk to another BMW dealer. They will not charge to check for outstanding rework/recalls. There must be a central check-point they can use.
I agree with the gas test of the coolant - but not at bmw prices. Incidentally, assuming the head gasket has gone, how do you explain the excessive pressure given that the system has a pressure relief cap which says it opens at 2 bar ? Do you agree that if the pressure cap opens at the correct pressure that you cant over pressurize the system short of exceeding the overflow capacity ? Have you ever seen such an effect before ? I havent, and I have had cars blow head gaskets in the past.
Also, in my experience of head gasket failures, they get progressively worse - the initial damage is likely to have been done months ago when I noticed the drop in coolant and topped it up assuming a leak, the new rad has been in for a few weeks and I've inspected it, it hasnt deformed . In addition, I have corresponded with another owner of a similar car who has changed the rad and cap and doesnt appear to have had a recurrence. These facts dont fit nicely with the head gasket theory. I will monitor closely and will pay for a coolant check if I suspect a problem.
Lastly, your last remark about bmw dealers not charging - not my experience, and bmw technical do not agree that there is a problem. In fact bmw suggest that I do pay them because, in their opinion, noone else is qualified to work on their cars - yet more advice I wont be taking.
Steve
corresponded
For reference, according to the BMW TIS/ETK cdroms, the recall on the E34s was related to changing the pressure relief cap as a solution to this exact problem. They may have specified a higher than acceptable pressure for the original caps resulting in failures. Is the 2bar rating on your new one the same as the old one?
JB
Thanks very much for your response - I suspect something of this kind based on internet searches. Bmw technical phone line deny any recalls on my car apart from a leaking gearbox plug ( did they top it up afterwards, I wonder....... ) I dont trust them though. The new cap states the same pressure as the old one - 2 bar. At 180 quid a pop, its not cheap ( all independents are out of stock ) so I will keep an eye on it.
Again, thanks for restoring my faith in usenet newsgroups, by being helpful and providing useful info.
Steve
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