Engine temps in hot weather

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XVar
Joined: Thu 24 Mar, 2011 17:58
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Location: Derby

Engine temps in hot weather

Post by XVar »

On my way home from work today I had the pleasure of sitting in standstill traffic for an hour, in 28°C with rain showers - so I couldn't even put the roof down :x. After about 45 mins of 1st gear crawling I looked at the engine temperature and noticed that it had rocketed into the red, about 1/3 into it. Is this to be expected with this weather? What would have happened if I'd stayed still for much longer? Luckily the traffic started moving shortly after I noticed it, the temp gauge went back to dead center after about 30 seconds of driving at 70mph.

Oh, and the best part - the reason for the traffic. Take That have decided to grace Birmingham with their presence. So armies of middle aged women with a bad taste in music ruined my afternoon :bad
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z3steve
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Post by z3steve »

I'd be interested to know the answer to this too.....
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aceman
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Post by aceman »

Warped head is the ultimate sacrifice for an over heated engine.
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hornel Z3M
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Post by hornel Z3M »

For a proper answer, the thermostat may not be working properly or you may have given it a bit of stick before the hold up. If it doesnt happen all the time ,then they are a possibility. :wink:
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Post by Guest »

The answer is no, it's not normal. Hot weather doesn't help the engine, but BMW design their cars, and so does everyone else for that matter, to operate in hot, cold & temperate climates, so were it mine, I'd be looking into things.

Anyway, I'm too busy recovering from my wishbone surgey & sulking as when I went to have the lignment done, it turned out my track rod ends are seized & now it has to go to the man with the acetylene, and only then the man with the hunter laser alignment.
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Badman gee
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Post by Badman gee »

its not normal, get this checked out.

today was hot but not as hot as some places abroad.

the car should have been able to cope adequately with today's temp.

mark
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Justin Time
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Post by Justin Time »

I've been a bit enthusiastic in mine today and on other days like today in the past and never had that experience. Best get that checked out, you don't want a repeat performance as explained above.

It's not normal.
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Phil
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Post by Phil »

Mmm - not normal. Even after prolonged high rev running like a track day I've never seen it anywhere near the red.
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macca
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Post by macca »

I would check to see if the fan is working.
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Post by Bill- »

No warning lights up.... :shock:
triumphted
Joined: Tue 30 Dec, 2008 19:34
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  Z3 roadster 2.8
Location: Essex

Temp Issues

Post by triumphted »

Xvar

I have been away from Zeds for a time now, but would like to offer a bit of advice here:

Your profile states a 2.8. This answer is 2.8 specific.

Firstly I do hope you have not suffered any damage as that sounds like it could be a close run thing if the head has got that hot.

The Zed has a tempered temperature gauge and as such MY experience from a very convoluted similar issue is that it does take some excessive temperature movement to shift the gauge.

The 2.8 is not as a matter of course fitted with an electrical radiator fan. It is fitted with a Viscous coupling that will rotate the rad fan at a speed lesser that the pulley speed most of the time.

Within the coupling is a fluid that expands with the temperature pushed out from the rad, and at pre determined temperature a mechanism within locks the fan to the pulley and then you have cooling driven at engine speed. My other posts specify the technical specs re temps ----i think.

This is my laymans explanation someone may come along and provide a more technical definition..

The point is the vicsous fans do have a history of failing sometimes quietly sometimes catastrophically. They have been known to come off and wreck the ancillaries which is ££££££££

Your symptoms are indicative of viscous failure, however, there are other culprits in the cooling system that you need to check out also;

The viscous can be checked by running the car up to temperature and pushing a rolled up newspaper between the fins. Prior to the car getting hot the fan will simply stop with little effort. If the viscous engages as the car gets hotter, basically as soon as the gauge starts to move further than middle your newspaper will be ripped to shreds -- Keep your fingers away throughout! This proves that obviously it is working. If not theres a problem.

You now ought to confirm it is only the viscous and not the rad causing the lack of operation. Mine had a blocked rad and was not transferring the heat to the Viscous coupling, it managed fine in normal traffic but as soon as i stopped in traffic the temp climbed as you suggest. You may need to test the rad with a heat meter of infra red thingy.

Water Pump, the pumps on the 2.8's have been known to be a problem, so whilst at it i would have the pump and thermostat changed. The originals pumps were, iirc plastic and simply give up the ghost, the revised parts are metal.

I seem to remember many saying the viscous and pumps were probably worth about 60k, ....mine failed at 64k.

If buying a Viscous personally i could only recommend BMW. I tried at least 2 maybe 3 pattern parts and all were faulty. It seems that if they are stored horizontally this fatally afffects the fluid within and they then fail to operate. BMW ones may not need this treatment see links below.

Good luck hope this is of help and that it is not too costly. The viscous from bmw is iirc £150 ish, rad similar. Couple of links here for you:


http://www.zroadster.net/forum/viewtopi ... highlight=

http://www.zroadster.net/forum/viewtopi ... highlight=

Regards

John
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XVar
Joined: Thu 24 Mar, 2011 17:58
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Location: Derby

Post by XVar »

Nope no warning lights or anything, it's usually bang in the center this is the first time I've seen it above. The fan was working the last time I checked, it's only today with the really hot weather that there's been an issue. Could it be a problem with the radiator, clogged up or something?

Edit: I posted this at the same time as the post above. Thanks for the extremely detailed reply John, I'll be sure to check out the things that you've suggested.
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Bill-
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Post by Bill- »

thermostat first after coolant check etc... the collant can boil over if yr lid aint tight, look at that as well if it was getting that hot you may have lost some coolant. look & top it up..
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Post by Bill- »

aaaaand check your oil levels... low oil will heat up your engine bigtime..
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Re: Temp Issues

Post by Bill- »

triumphted wrote:Xvar

I have been away from Zeds for a time now, but would like to offer a bit of advice here:

Your profile states a 2.8. This answer is 2.8 specific.

Firstly I do hope you have not suffered any damage as that sounds like it could be a close run thing if the head has got that hot.

The Zed has a tempered temperature gauge and as such MY experience from a very convoluted similar issue is that it does take some excessive temperature movement to shift the gauge.

The 2.8 is not as a matter of course fitted with an electrical radiator fan. It is fitted with a Viscous coupling that will rotate the rad fan at a speed lesser that the pulley speed most of the time.

Within the coupling is a fluid that expands with the temperature pushed out from the rad, and at pre determined temperature a mechanism within locks the fan to the pulley and then you have cooling driven at engine speed. My other posts specify the technical specs re temps ----i think.

This is my laymans explanation someone may come along and provide a more technical definition..

The point is the vicsous fans do have a history of failing sometimes quietly sometimes catastrophically. They have been known to come off and wreck the ancillaries which is ££££££££

Your symptoms are indicative of viscous failure, however, there are other culprits in the cooling system that you need to check out also;

The viscous can be checked by running the car up to temperature and pushing a rolled up newspaper between the fins. Prior to the car getting hot the fan will simply stop with little effort. If the viscous engages as the car gets hotter, basically as soon as the gauge starts to move further than middle your newspaper will be ripped to shreds -- Keep your fingers away throughout! This proves that obviously it is working. If not theres a problem.

You now ought to confirm it is only the viscous and not the rad causing the lack of operation. Mine had a blocked rad and was not transferring the heat to the Viscous coupling, it managed fine in normal traffic but as soon as i stopped in traffic the temp climbed as you suggest. You may need to test the rad with a heat meter of infra red thingy.

Water Pump, the pumps on the 2.8's have been known to be a problem, so whilst at it i would have the pump and thermostat changed. The originals pumps were, iirc plastic and simply give up the ghost, the revised parts are metal.

I seem to remember many saying the viscous and pumps were probably worth about 60k, ....mine failed at 64k.

If buying a Viscous personally i could only recommend BMW. I tried at least 2 maybe 3 pattern parts and all were faulty. It seems that if they are stored horizontally this fatally afffects the fluid within and they then fail to operate. BMW ones may not need this treatment see links below.

Good luck hope this is of help and that it is not too costly. The viscous from bmw is iirc £150 ish, rad similar. Couple of links here for you:


http://www.zroadster.net/forum/viewtopi ... highlight=

http://www.zroadster.net/forum/viewtopi ... highlight=

Regards

John
:oops:
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BonBon
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Post by BonBon »

If the water did not boil out of the radiator cap then there should not be any damage to the head.
If the Temp gauge is generally stable in the middle - then my bet is that the fan did not kick in when temp went up due to idling. There are 3 possibilities:
1. The fan is defective - check this by turning on the AC and seeing if the fan comes on.
2. The fan was not activated due to defective radiator temp sender unit
3. The fan was not activated cuz the water level was too low and the sender unit was not able to measure the correct temp and open the fan.

Cost is in reverse order to list above.
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TitanTim
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Post by TitanTim »

The temp gauge should stay in the middle of the range constantly even if sitting in traffic at boiling temps.

Your thermostat is probably knackered. I'd replace it anyways.

Tim.
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triumphted
Joined: Tue 30 Dec, 2008 19:34
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Location: Essex

Temp Issues

Post by triumphted »

Of course check the basics as the above correctly state.

Apologies I should have said that.

I would hope for a thermo issue but experience tells me that this will be viscous related, especially the fact it has ocurred in this 'extreme' weather.

The difficulty is diagnosing the failure of the coupling. I remember running mine on the drive at 3k revs for 15 mins in about 70F weather and not managing to trigger it.

Luckily I had access to carsoft and could continue to monitor the live data and the water temperature so was SURE it was not activating at the correct temp.

As all have alluded to, this is a potentially costly problem if you get caught out, so if you do not have the knowledge time or confidence i would find a sympathetic Z3 / BMW specialist and make them read all the suggestions here. Mine went through a well respected specialist and they continually failed to test the viscous properly. They thought idling for several hours would achieve the temp, it does not.

For me it only ever happened after a 20 min run at 70 mph then a sit in stationary traffic for 5 to 10 mins.

You will also have cooked your oil a bit today so you probably want to change that soon as well.

good Luck
Last edited by triumphted on Mon 27 Jun, 2011 20:43, edited 1 time in total.
triumphted
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  Z3 roadster 2.8
Location: Essex

Post by triumphted »

Bon Bon

2.8 does not have a sender unit. It is viscous.

Bill

What is the embarassed for? I am offering sound advice imo.

I am puzzled and do not wish to hijack this thread. Just want to help a member with a problem.
Last edited by triumphted on Mon 27 Jun, 2011 20:46, edited 1 time in total.
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BonBon
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Post by BonBon »

:oops:

I read the problem and proceeded to post.

My input will benefit 1.8, 1.9 & 2.2 if they have a similar problem.
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XVar
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Location: Derby

Post by XVar »

triumphted wrote:Bill

What is the embarassed for? I am offering sound advice imo.

I am puzzled and do not wish to hijack this thread. Just want to help a member with a problem.
I think he was alluding to the fact that you gave a much more detailed reply than his, nothing untoward :)
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Jamezee
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Post by Jamezee »

TitanTim wrote:The temp gauge should stay in the middle of the range constantly even if sitting in traffic at boiling temps.

Your thermostat is probably knackered. I'd replace it anyways.

Tim.
I have never seen mine move over the middle in all conditions
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Zed Carer
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Location: Wakefield

Post by Zed Carer »

Having read all the above posts just thought that I'd my thoughts:

Having checked the basics (coolant level, leaks, etc) then personally at this stage I would forget about the thermostat as on the 6 pots this fails in the open position; i.e. the equivalent of having no thermostat and the engine therefore runs cold - there are plenty of posts on this.

The older water pumps had a plastic impeller and this can come loose on the spindle and effectively there is then nothing to circulate the water. This would eventually result in a rise in temperature.

It does seem like the viscous coupling has failed to engage as when this does engage the fan runs at the same speed as the crankshaft and it sounds like a Merlin engine. On Z3's with aircon the aircon fan generally provides enough airflow through the radiator so the viscous fan coupling only becomes effective in extreme conditions - IIRC Mike Fishwick has posted on this before.

A partial blockage of the radiator could also cause overheating when stationary in hot weather so I'd be inclined to remove the radiator and back flush it and take the opportunity to check the water pump at the same time. If you've also got the old style thermostat with the plastic ears then change it for the later one with the metal ears as the plastic ears will fail eventually.

If the above doesn't sort it then you're down to the viscous coupling and this is the expensive bit.

Of course it could be a failed sender unit - this just sends a signal to drive the display and doesn't actually activiate the fan but I've not seen any posts on these failing and the temperature did return to "normal" when you got back up to speed.

Good luck.
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Frank.A
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Post by Frank.A »

If the original type pump with plastic impeller is installed and it is slipping on the shaft at idle, then even if the rest of the system is in A1 condition, the engine will still overheat as the coolant is not being circulated.

If the pump is working at idle overheating will take some considerable time due to the fact that an aluminum engine dissipates heat very efficiently.

This design of pump with plastic impeller has been fitted to most marks in the past 10/15 years with the same result.

My bet would be the pump.
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Beemer Man
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Post by Beemer Man »

Does anyone know when/what model year BMW switched from using the old type water pump with the plastic impellor?

In other words, is my July 2000 2.8 Zed at risk?

I had one fail a few years ago on a 1998 E 39 520i I owned at the time, and although the temperature guage went off scale, nothing else untoward happened.

I had the pump changed for one with a metal impellor and a friend is still running the car happily with another 30-40K miles on the clock (now 150K+).
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jayson f
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Post by jayson f »

C3 BMW specialist www.c3bmw.co.uk, Make a note of this company they are great they sell parts made by companys that supply bmw at reduced cost because they dont have bmw stamped on them. They also sell metal finned waterpumps £36.00 plus vat, and thermostat housings and thermostats for £37.00 plus vat all made in germany. This is for six cylinder models but they do loads of other parts for all bmw models. My 3.0 has done 56,000 miles and i changed both as im going to France soon for two weeks and for that money it seemed worth it, also very easy to change on six cylinder models . :lol:
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Post by Jamezee »

I am not very mechanically minded so cannot offer any advice on that
but I can have sympathy with your car.

I was stuck in a traffic jam in north wales today for well over an hour with the roof down...the temperature gauge sat bang in the middle and I burned :dunce:

Every flippin time I forget the sunscreen and remember the cap all too late.

I now look very silly with sunglasses marks on my face :dunce: :dunce:
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Beemer Man
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Post by Beemer Man »

"jason f"-thanks for the reminder about C3 BMW Specialist-I used them years ago (in my E30 M3 days) and had completely forgotten about them.

I must give them a try again.
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XVar
Joined: Thu 24 Mar, 2011 17:58
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Location: Derby

Post by XVar »

Thanks for all the advice so far :thumb: A few questions:

1) After my drive home (30 minutes down the motorway) today I measured the temperature of the radiator using an infrared thermometer, is it normal for it to be 35°c on the left, and 70°c on the right, getting progressively warmer left to right? The temperatures are consistent vertically, so the left side is 35°c top to bottom, and the right side is 70° top to bottom. There don't appear to be any dead spots, so I'm not sure if this rules out a radiator blockage?

2) Should the radiator fan be able to be spun freely by hand with the engine off after a decent run? I was under the impression that when the viscous coupling gets hot it "locks" the fan so it runs with the engine, so when its engaged and hot you shouldn't be able to spin it by hand?
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MickJ
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Post by MickJ »

Don't think you will find that it completely locks the fan when hot, have a read of this:

http://www.daviescraig.com.au/Fan_Clutc ... ntent.aspx
triumphted
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Post by triumphted »

Xvar

How did you get on with this?


John
Bill-
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Post by Bill- »

triumphted wrote:Bon Bon

2.8 does not have a sender unit. It is viscous.

Bill

What is the embarassed for? I am offering sound advice imo.

I am puzzled and do not wish to hijack this thread. Just want to help a member with a problem.
I've enjoyed reading your thread about the fan john, Very informative. Dont worry about the smily bloody silly arn't they.
triumphted
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Post by triumphted »

No Probs Bill

- from a different generation don't really understand them... Life just gets more confusing eh. :D 8-) :oops:
Mac The Tank
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Post by Mac The Tank »

XVar wrote: 1) After my drive home (30 minutes down the motorway) today I measured the temperature of the radiator using an infrared thermometer, is it normal for it to be 35°c on the left, and 70°c on the right, getting progressively warmer left to right? The temperatures are consistent vertically, so the left side is 35°c top to bottom, and the right side is 70° top to bottom. There don't appear to be any dead spots, so I'm not sure if this rules out a radiator blockage?
I'm sure that's the radiator doing its job - reducing the temp of the water/coolant running through it. A blockage would show cold spots/lines that look out of place

Not had a Z3 rad out though to have a proper look at construction, so please don't read this as gospel...


Mac
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triumphted
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Post by triumphted »

Hi Xvar

Just curious if you managed to sort this fault out?

J
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XVar
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Post by XVar »

Not yet, it's at the top of my list to get the radiator/water pump replaced - my local garage quoted £80 labour for the lot which seems pretty reasonable. Also looking at replacing the viscous with an electric fan just to make sure that all bases are covered. There's been no sign of overheating since that once but I'm pretty sure that it's only going to take the weather getting really hot again for it to reoccur.
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Mr Silver
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Post by Mr Silver »

Save your money, it will be another two or three years before we get another hot day like that again! It's pouring with rain here...

...miserable, dull, non-Zed day! Can't even get it out to clean it!

I'm going to sulk some more...
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XVar
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Location: Derby

Post by XVar »

I did think that, but knowing I'm only one freak hot day away from a blown head gasket is pretty unnerving, think I've got to do it as crap as our weather is. The weather's alright here today, fine top down weather for the drive home from work :drive
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