Overheating problem

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dazthephot
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Overheating problem

Post by dazthephot » Thu 17 Apr, 2008 22:18

Hi guys and gals. First of all a warm hello to you all from a new member.

My problem is overheating related. I have a 2000 plate 1.9 M43. Topaz blue - lovely, but it has started to overheat when the engine is warm and i am sat at idle. When i am travelling the temp goes down, when stationary i have to rev the engine and turn the heater on full blast to bring the temp down. The blower was hot now is only blowing cold. My local garage (non BMW) suggested head gasket but i refuse to believe that - as i turned the car off immediately when the temp went red. Originally i thought thermostat as the water level in the exp tank was way high and not going down, it took 3 days with the cap and bleed screw off before it went down. Now i suspect water pump. It has 72k on the clock but i only do about 3k a year.

Please give me your suggestions.

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ribs
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Post by ribs » Thu 17 Apr, 2008 23:24

Hi... I have the same engine in the 'little red roadster'.

I had the same problem, but funny enough only once. I drove the car 120 miles a day, to and from work for a year and once in traffic on the motorway it started to overheat. The needle seemed to increase in jumps when the car was stationary, almost as if the thermostat was working, but letting in only hot water each time. The needle never quite got in the red through, always started to come down just in time.
When the traffic started moving it seemed OK.

This only happened for that one day through. I asked the dealer about it when the car went in for it next service. His first question was "did I hear the fan come in?". Obvious really, but I really couldn't remember.
He said that it could have been a loose connection on the fan, if it did not come on, or a sticky thermostat if the fan was working OK.

He gave me a quote for replacing the thermostic, but as it has only happened once I just filled it.

Can I suggest you take it to your dealer and let them have a look. It always causes a stir when I take mine in and they are really very helpfull.

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Ash_88
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Post by Ash_88 » Fri 18 Apr, 2008 00:29

if the heater is blowing cold air out then you probably have an air lock and will need to bleed the system

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mrluke
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Post by mrluke » Fri 18 Apr, 2008 09:53

JUST a quick question

i also have a 2000 1.9 z3

WHen u first start from cold start , does some sort of fan/pump kick in and sound like a Jumbo hairdryer untill it reaches a decent temeperture , and then turn it self off ?

im only asking as mine always does this every morning , and that way i know my car has warmed up :D

was just wondering if urs done it

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dazthephot
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Post by dazthephot » Fri 18 Apr, 2008 15:57

Hi mrluke, yes i think it is the air conditioner (not the AC) that makes that noise. It usually starts moments after starting the car, lasts for a couple of minutes then goes off. I too usually wait til it's finished before setting off. I've looked at it cos at first i thought it was where the air conditioning filter was but it isn't.

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dazthephot
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Post by dazthephot » Fri 18 Apr, 2008 15:59

hi ribs, the fan doesn't come on at all. i am just gunna have a look with the AC on and see if that makes a difference.

I can start the car and leave it running, the temp will stay in the middle, but the minute i have done about 10 miles and the engine is hot it overheats at idle. i have never let it go that far that there is steam coming out though so hop0efully there isn't too much damage.

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dazthephot
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Post by dazthephot » Fri 18 Apr, 2008 16:36

just tried again, the fan comes on when the AC is switched on but before i did that i let the car warm up. the heater is blowing out stone cold air, almost as if the thermostat wasn't even there so i am going to change that first.

has anyone got a paint by numbers method of doing this please?

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Post by Zed Carer » Fri 18 Apr, 2008 18:33

dazthephot wrote
has anyone got a paint by numbers method of doing this please?
Link below to all you need to know about replacing thermostats

CLICK

Must admit that mine has gone (1999 2.8 M52TU) and I have been investigating DIY following Mike's excellent instructions but garage still needs sorting and its a bit cold/wet for working outside. I've booked mine in with Teeside Auotech who've quoted £128 for drain, flush and new thermostat. A bit of a cheat really but I've only had the car 4 weeks and I want to drive it.

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dazthephot
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Post by dazthephot » Fri 18 Apr, 2008 20:05

That's great thanks, and i don't blame you. I've only had the car a year and just done 2500 miles, criminal really but last years floods put the dampner on any open top fun!!

maxman
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Post by maxman » Fri 18 Apr, 2008 21:47

Your overheating problem could be water pump related.As the car has overheated it is a good idea to change the the thermostat.

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jamila
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Post by jamila » Fri 18 Apr, 2008 22:11

I had a similar problem last year; I found that the radiator had a crack in it. I would suggest having a diagnostic check done on it, I've found with non-BMW garages (from experience) that they 'think' its one thing, fix it, and if the problem continues they keep taking guesses at your expense. You need to go somewhere where they actually know what they’re doing, try a specialist garage maybe. Good luck.
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domross
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Post by domross » Fri 18 Apr, 2008 23:35

Order of likelihood 1. airlock...bleed with heater on
2. Fan...temperature switch not turning it on
3. thermostat...although unlikely if it is stuck it will be stuck open as the car is cooling when driving which indicates that water is flowing through the radiator...thermostat opens and closes at certain temps to allow this
4. water pump

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AndyBass
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Post by AndyBass » Sun 20 Apr, 2008 11:15

I think from your description that your fan is not coming on to cool the engine when you are standing still. If the blower runs cold at this time when the engine is idling it seems to be a symptom that the water pump is failing to circulate the water until you rev it and get the water pump spinning faster. Check the fuses to the electric fan and consider a new water pump.
We all have a photographic memory, just some don't take the lens cap off!

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dazthephot
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Post by dazthephot » Sun 20 Apr, 2008 22:24

I think i'll start by draining the coolant but i'm not sure how to do that with the heater on, does that mean leaving the ignition on whilst keeping the heater temp dial turned to hot and running the internal blower? if so what does that achieve?

i've also seen mention of a bleed screw on the engine block. Where exactly (pic if poss)

also should i remove the bleed screw from the top of the radiator at the same time of the radiator cap whilst draining? odd ? i know but every car i've flushed in the past has just been a case of remove the rad cap then pull off the bottom hose and away you go.

the bently manual is awful dear, but is it worth it?

the temp sensor, is that the only one in the side of the rad?

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SpunkyM
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Post by SpunkyM » Mon 21 Apr, 2008 13:38

New water pump required. Definitely. Take my word for it.
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dazthephot
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Post by dazthephot » Wed 23 Apr, 2008 09:53

How bizarre, i tried to limp into Stratstone BMW in Hull yesterday and didn't get more than a couple of miles before i had to get the RAC to rescue me. They towed me into BM so they could diagnose the snag.

They called after a full day and said they needed more time as they wasn't sure what the problem is, now if they don't know what chance have i got?

They reckon the thermostat is working, didn't think it was the water pump and are now looking at the head gasket.

I was fairly sure it could only be the Wpump or Tstat, but i'll keep you all posted - in the spirit of the forum.

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mrluke
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Post by mrluke » Wed 23 Apr, 2008 12:06

Problem being with BMW

my airbag module went , because they coudnt get no communication from the module they suggest changing ' the seat sensor'

now im no car mechanic , but i would assume no module communication ment either a broken wire or a broken module .

i would recomend a good indie , as bmw and indies machines are the exact same !

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SpunkyM
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Post by SpunkyM » Wed 23 Apr, 2008 13:34

Most obvious thing to me is that cold heaters means no water circulating (the circuit is separate to the one with the thermostat in). No water circulating = knackered water pump.

The head gasket can't be ruled out though - when this goes, it pushed gases into the cooling system and creates an airlock, but you can generally tell this as you get the gases coming out of the expansion take and it 'puffs' with engine rpm if you know what i mean.

It has to be one of those two, I'm certain of that.
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dazthephot
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Oh My God

Post by dazthephot » Thu 24 Apr, 2008 10:25

well try this for size:

The thermostat locked shut, this lead to a failed water pump which in turn led to a knackered head gasket which now leads to a £900 bill.

I overheated once and turned off the engine straight away surely BMW's are made of tougher stuff - i guess not. I have had a string of beemers and this is the first one that has ever cost me money. I paid £7495 for it in April last year, i've put 2500 milkes on it and including this bill will have paid £1250 in repairs so far, just remind me again why i love the car so much???

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AndyBass
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Post by AndyBass » Thu 24 Apr, 2008 12:16

Thermo locked shut!! Now that's pretty rare. They usually break and remain open leading to lower engine temperature not the other way round. Desperately unlucky there I think.
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dazthephot
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Post by dazthephot » Thu 24 Apr, 2008 18:39

Desperately unlucky........yes that's what i thought. I can't help thinking though that the BM techs have fed me a bit of a line cos they can't find the snag. It's not as if i run the engine until there was white smoke everywhere.

I guess i'm annoyed cos my engine knowledge ends at straight mechanics, whatever happened to a nice suck, squeeze, bang, blow engine?

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SpunkyM
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Post by SpunkyM » Mon 28 Apr, 2008 12:03

A thermostat locking shut is not going to lead to a failed water pump, that's complete nonsense. The thermostat is closed until the engine is up to temperature anyway... no way it will damage the water pump.

But water pump and / or head gasket are what I said. You don't always get white smoke when the head gasket goes, it depends exactly where the failure is. Difficult to ascertain what was the root cause though, I wouldn't expect the head gasket failure to damage the water pump, but you could expect the water pump failure to warp the head through overheating which could possibly lead to gasket failure.
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domross
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Post by domross » Mon 28 Apr, 2008 22:12

Thermostat stuck shut would lead to the car overheating on it's own as there won't be any coolant going thru the rad....is it definite that the head gasket has gone...have they pressure tested it? or are they speculating...I would go for the t/stat 1st and then if that doesn't solve things go for the rest??

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dazthephot
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Post by dazthephot » Mon 28 Apr, 2008 22:51

They had the car for one day and called to say they had to do more tests. When they called they said they had been testing the head gasket as they thought the tstat was ok but they weren't sure about the water pump. They then called and said it was definately the head gasket, caused by a failed water pump. They recommended putting on a new tstat as well as it would probably go at some point in the near future. You know your stuff spunkyM i bow to your greatness. In any case i am reluctant to trust anyone but BMW, a bit paranoid i know but on the plus side it will have a 2 year parts and labour warranty. In the past if a car has overheated you could normally wait til it cools down and limp home, i guess zeds aren't as strong as i thought.....unless it was on it's way out when i bought it and driving it for more than 2500 miles would have done it earlier. I just want it back now, i've been putting the extra work in to pay for it.....now that's committment.

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dazthephot
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overheat

Post by dazthephot » Thu 08 May, 2008 21:02

just an update. the radiator has had to be replaced as well, as it was blocked???

£989 in total, rad, tstat, w pump, head gasket.

is it me or have they just replaced everything cos they don't know what the snag was or have they done right?

now the new radiator is wobbly cos they haven't replaced the top rubber mounts, the check engine light is on and it feels like it's holding back on acceleration.

i'm not new to beemers but i'm seriously thinking of another manufacturer.

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domross
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Post by domross » Thu 08 May, 2008 21:39

Hmmmmm.....so basically everything but the pipes and heater matrix?!?.....personally v dubious as to whether all needed changing...they seem to have gon for the 'if you throw enough sh!t some of it is bound to stick' method...as for other things, go back and jump up and down v.v. loudly!!!
Never heard of a t/stat sticking closed (open yes) but the h/gasket personally have my doubts?!? Ask to see old rad ,easy check on blockage stick a hose in one end if water don't come out the other then blockage correct...if water does come out then no blockage.

IMHO indys are often better for older models as they simply they have more experience in dealing with them...and therfore are more likely to have seen a particular problem crop up before
Hope you get it all sorted

maxman
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Post by maxman » Mon 12 May, 2008 21:45

In a word i think you have been ripped off by a garage that does not have a clue and on top of that it still is not running correctly.
The blocked radiator was the most likely cause of your problems.
If you have not paid the bill ,offer to pay for the rad plus the labour for its replacement,if they moan ask them to justify the other repairs. :head:

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Post by Guest » Tue 13 May, 2008 12:48

I bet the water pump was the likely culprit - the plastic impeller can come loose on the steel shaft, slipping enough at low speeds to cause high temperatures. At higher speeds the slip is a smaller proportion of the speed, and more air is flowing through the radiator too.

It's a well-known problem, and one I would have checked first, along with the thermostat, which on the 1.9 is a cheap enough item (not like the electrically-controlled type found on the double-VANOS engines. It can fail in the closed position, but a quick boil-up in a pan will soon tell you if it is defective.

It is just possible that the radiator was blocked by an accumulation of nitrate sludge from the antifreeze, but very doubtful.

In any case, the odds on the pump, thermostat, radiator, and head gasket all failing at the same time are astronomical - you have been seen off, but proving it is another matter. I'm surprised they did not also claim the fan was defective, and add one to the shopping list!

The only answer is to find out how your car works, and check things yourself - you may make a few errors, but it will be a lot cheaper, and you will learn something every time.

The Bentley manual is not as good as they claim - see my review in the Z3 Knowledgebase. The Haynes is Ok on the engine (as per the 318iS) and the BMW ETK/TIS disks are excellent, but assumes you have a good basic knowledge. Buy both, and spend time reading both.

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SpunkyM
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Post by SpunkyM » Tue 13 May, 2008 14:42

Feel like I'm repeating myself here. The giveaway is that the heaters didn't work. This has nothing to do with a blocked radiator or a closed thermostat as it is a completely separate circuit.

The reason the heaters didn't work is because there was no coolant circulation either because of:

1) The water pump wasn't pumping it around
2) There was an airlock in the system because of gases being pumped into the coolant from the head gasket failure.

I think they were probably justified in changing both and looks like they added the radiator and thermostat for good measure (but probably unnecessarily). I'd be tempted to say just walk away and be happy it's fixed if it wasn't for the fact that you now have the light on. You obviously need to get it back to them to find out why.
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dazthephot
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Post by dazthephot » Sun 18 May, 2008 18:37

Right then, got the car back thankfully but £989 lighter. The check engine light turned out to be a knock sensor problem which they sorted for free.

I think you could be right about the head gasket cos i had a definate airlock in the system. The water level was right up in the expansion tank and wouldn't go down. I tried the burping scenario and leaving the cap off along with the bleed screw for a couple of days and it made no difference.

In hine sight (spelling) i should have first drained the cooling system, this would have revealed the blocked rad, then checked the tstat to prove this and checked the double temp switch for fan operation, then gone down the water pump route and finally had a head gasket pressure test. Maybe then i would have given up and taken it to a specialist. I am now armed with all three sources of info for the car and hopefully will be better equipped to deal with stuff myself.

I bought the car as a future investment, when me and the missus are old and gray we will still have our highly collectable Z3 to drive around in, i just have to get it through the next 30 years or so....wish me luck, i hope this forum is still going. Cheers guys i look forward to the next chapter....daz.

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SpunkyM
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Post by SpunkyM » Mon 19 May, 2008 13:45

Glad to hear you are all back up and running Daz. Now enjoy the summer in your "cool" Z!
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dazthephot
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Re: Overheating problem

Post by dazthephot » Fri 19 May, 2017 15:26

For no other reason than to re-visit this thread.
9 years on, still have the same zed and despite one or two minor issues i can't complain about this car. 104k now and it's the missus daily runner and she still gets compliments about how good it looks.

One thing for sure though, time i flushed the rad!!!

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colb
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Re: Overheating problem

Post by colb » Fri 19 May, 2017 16:32

The question asked earlier in the thread by mrluke regarding the noise of a fan running when starting first thing in the morning caught my eye. The answer is its is an air pump that forces fresh air into the exhaust side of the engine to lower emissions on a cold start when the engine will run rich. The fan/pump is housed in a black cylinder on the right hand side of the engine and a plastic hose runs up to the top of the engine where it connects to a one way valve into the exhaust side of the engine. Should this valve fail and let hot gas back it will melt the hose. Some people take the whole thing out and fit a blanking plate to the valve.
Deleting it will not cause any problems at MOT test time when they test the emissions.
The only other problem that may arise is the fans bearings packing up resulting in excessive noise from it. If that happens bin it and fit a blanking plate to the valve.
Colb
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