Cooling system woes

[JimmySpeed]

This morning, I checked my coolant level as I have a small dribble that comes from my expansion tank cap. This dribble has been there since I got the car, and even after replacing the exp. tank cap, it still dribbles a little. The level was fine this morning (above min.) so I put the cap back on and went on my way.

Perhaps I didn't tighten it fully though, because I stopped at a petrol station to fill my washer bottle after doing about 50 miles since the morning and there was coolant sprayed all over the engine bay and the origin was clearly the exp. tank cap, like it had exploded from the exp. tank cap. The cap was still in place though.

It was too hot to check the level there and then so I set about home and all of a sudden the "coolant temperature" warning came on and the engine temp shot up past the halfway mark where it has ALWAYS lived up to now. I pulled over immediately and let it cool, drove a few more miles till it did it again and so on. After the first time that it shot up within seconds, whenever it got hot after that it increased gradually from halfway upwards, no shooting upwards like the first time.

Also, I put the heater on max and the highest temperature to help get rid of some of the heat, and to begin with it was hot, but by the time I got home the heater was blowing cold even on max.

So my question is, is this all caused just by a lack of coolant (from my coolant loss earlier due to impropper tightening of exp. tank cap & leaking expansion tank), or has my water pump given up and thats whats causing this? Or could it be both?

It will be about 3 more hours before the car will have sat long enough for me to open the exp. tank cap and have a look, but when I do, how will I know if my water pump is still working - is it a case of if you see coolant circulating around the expansion tank then the pump is working?

Thanks

[JimmySpeed]

The engine cooled enough for me to check it out and I discovered an empty expansion tank - it took 10L to refill the system so it lost ALOT of coolant today, all through the cap? (I can't see evidence of any other leaks)

The heater is now hot again but what is concerning is that the front fan (the one on the outside of the engine bay closest to the front grills, as opposed to the one inside the engine bay) did not come on at all while I had the engine running. The climate control was set to its hottest and the car wasn't 100% cold, the needle was just out of the blue - would this explain it?

Lastly, when the climate control fan was set to max, there was an intermittent wooshing sound when I put my head back into the engine bay. It sounded like a fan going fast then slow then fast then slow. It was its intermittent nature which concerns me, I have heard a similar noise on cold startups for around 10-20 seconds normally, but that noise is constant until it goes off.

[AW8]

I have heard that expansion tank failures can be linked to water pump problems, however, it is not true that a damaged or failing header tank means the water pump is dying. I think it is more the case that a tired water pump can place additional heat & pressure on the header tank & thus cause a slightly weary header tank cap or associated bleed valve, (I think thats what it's called) to fail. Fwiw I had new top hose, then I fitted new header valve/screw many months later, then I replaced the tank a few weeks after that. Water pump failure not until approx 20k miles thereafter.

From what you are saying it seems you may have a leaking header tank or cap......Don't disregard remote chance of a leaking top hose either. A very small leak from same can be hard to detect initially & coolant spray in similar area to coolant from a failing header tank......That said one thing is for sure - if a top hose totally failed when car warmed up then you would definitely have known about it......as would any following vehicles.

As for whether your leak is being caused by your water pump I simply don't know.

My water pump was changed very recently though by an indy & not by me. The pump had not totally failed & siezed, but I had noticed an increasing loss of coolant. Initially I had suspected air in the system. I knew I had a problem when for the 3rd time in a few days I got a check coolant dash message. This was when 30 mins from the Bristol meet. Jason & his crew looked at my car & all that could be seen initially was a very slight leak under the area near & below the water pump. Later on we saw significant coolant leaking from under the car. Even then it was impossible to totally ascertain the exact source without removing the undertray &/or causing a pressure test to be performed. Jason understandably did not have pressure testing kit with him at the Bristol meet. Play was confirmed on the coupling between the main fan & water pump.

I managed to drive back home taking it easy over 3hrs. My coolant having been topped up prior to the return journey proved enough to get me home. I booked the car in to a closer to home BMW indy to get car sorted & only used car for very short & few trips until it could be seen. Even in this short time I noticed a progressively more obvious leaking followed by noise coming from what I believed to be the water pump.

I cant comment as to the efficiency of your water pump but I am prety certain that if it is failing & it siezes you will know about it. Worst case scenario would be other associated damage whether belts thrown & mangled or worse damage. I must emphasise this is worst case scenario.

Local indy pressure tested mine & indeed confirmed problem was the pump and a new BMW sourced exchange item was fitted. I also had the stat done at same time simply because this made sense as it is in same area & good preventative maintenance to change both at same time, (rather than having to cause everything to be ripped out again). At same time I also had major hoses top & bottom changed as well as the fan belt & a/c belt.

You mention the front fan. This is the auxillary a/c pusher fan. These are widely known to fail on the petrol E53, indeed there have been recalls in the USA re this part. Regardless of what BMW UK or UK dealers may say I can assure you that the part number is the same for UK & USA models of the petrol E53. This fan should operate with the a/c on & certainly when car warm & set to max when cars is statict. It's purpose is to assist cooling when the a/c is on. In particular this reduces temperatures when a/c is on in slow or halted traffic. I believe that to change same is a full bumper off job, there may be shortcuts for those experienced or prepared to have cut hands. Either way the fan isn't cheap & there weren't any used ones available nationally last week. Hopefully the whirring noise you heard was the aux/pusher fan working.........Fingers crossed for you.

I have posted re the cost of having all this work done plus new coolant. I wont post here as I don't want to worry you unduly. If you really want to see the figures then check out my recent thread on my car being sorted.

On a more positive note the only problem might just be something as simple as a leaking header tank cap. If it makes you feel better I have had to replace a header bleed valve on old tank to sort a leak then a few thousand miles later the entire header tank. The water pump failed some 15-20k miles later so no clear association between the two items.

My advice is unless certain it's cap or tank then keep it topped up, keep temps as low as possible by taking it easy & get it checked asap by a professional using pressure test equipment. I believe yours is a 4.4i prefacelift like mine but with an LPG conversion, (checked after trawling posts). I personally would keep the LPG switched off until this is sorted. No link with the LPG & the leak but . My limited knowledge & memory of LPG systems is that they can generate additional engine heat........clearly something best avoided for now. I would avoid driving it when low on coolant, would keep spare water securely in the car & would pull over as soon as I saw temp gauge rise or check coolant message. Certainly you should not drive if heater stops working. By all means use heater to check if coolant running dangerously low but don't drive it if heater stops working as there is obvious potential for serious failure. If you have to release the header cap then only do so once cooler & by, (very-very), gradually undoing the cap whilst covering same with a large cloth to prevent it spraying up, causing excessive further coolant loss &/or burns to yourself from hot coolant.

Good Luck & please keep us updated.

[JimmySpeed]

Thanks very much for the detailed reply AW8. I read it at about 4am and was at a well respected Indy 20 miles away at 9am. I was in 2 minds about going to a garage or just "waiting and seeing" but reading your post helped me decide that the right thing was to deal with any potential problems before they caused further damage.

Turned out that my expansion tank neck was warped slightly (oval shaped instead of round) hence not a proper seal with cap. The pump was fine and pressure test result didn't show any other issues in the cooling system. They will change the tank and cap and renew the coolant for me (needed doing anyway).

I also have had them check a number of other things and replace all bake brake friction elements, change the 4 rear carrier bushes, read fault codes which revealed a bad camshaft pos. sensor and have that changed, and diagnose a slight wheel wobble for me which they will do once the coolant system is sorted but suspected to be a warped front disk.

I dont normally have so many things done at once so that I can spread the cost a bit, but this time it just made sense to leave them the car for 2 days and get all of this sorted. I even have an e34 520 auto as a loan car which is fun!

[AW8]

You were right to get it checked. I did my header tank myself & whilst it sorted issues at the time I took a slight chance there weren't further hidden leaks.

At known issues will be tackled in one hit, within a reasonable timescale & by persons who have experience & time to do the jobs quickly & properly.

I have prior read that the E34 520 is underrated.......Sure it's not an M5 but it's often fun to have a change of scenery

[JimmySpeed]

It's a fun car to drive - it's not fast, but it's so uncomplicated that you really feel like you are 'driving'. It's my first time driving anything decent of that age and I now know why people love the older BMW's, modern cars have their plus points (e.g i feel 10x safer carrying my kids in the X5 than i would in the e34) but a connected simple driverroad experience is not one of them.

[JimmySpeed]

[quote=""AW8""]You were right to get it checked. I did my header tank myself & whilst it sorted issues at the time I took a slight chance there weren't further hidden leaks.

[/quote]

I had considered just changing it myself previously when the leak was first discovered, however after yesterday I wanted the pressure test to see if anything else was required. On top of that, once I've paid the garage for their time in checking the system, I may as well have them do the job as the check becomes effectively free. They've also done a few other bits without charge because I am having so much work done

[AW8]

Glad it's working out well.......I too felt awkward getting garage to do pressure test with view to me doing the pump. I also bottled it a bit for fear of biting off more than I could chew & particularly in absence of certain tools & our garage being full of items in we have in storage.