what thermostat???

zedonist said:
No problems Jim ;) Where's the picture of that Z3?
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Being developed as of this afternoon. QShouldn't take more than 10 days or so to get back to me if the mail doesn't strike. Hope the old Brownie still takes good pics after all these years but the film was pretty old so fingers crossed there's an old timer that remembers how to develop film. Probably still some of our wedding shots from 72 on there and pics of the brats when they were babies. Excited to see what's there. Thanks everyone for pushing me to once more take up the camera. JIM
 
zedonist said:
Plus does moving to Seattle improve cooling in a Z3, may have to try it.........
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Probably not, but you can legally buy pot in the state now so probably wouldn't worry about it too much, as long as it gets you as far as a fast food place. JIM
 
You could always make a pin hole camera from an old shoe box, or just make a sketch with a crayon........
 
Moving from Arizona to Seattle definitely improved my cooling system, although I must say that I never had any issues in Phoenix. The Z always cooled well even at speed in the middle of summer.
 
Rudyrov said:
Moving from Arizona to Seattle definitely improved my cooling system, although I must say that I never had any issues in Phoenix. The Z always cooled well even at speed in the middle of summer.
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So, no overheating problems, must be the pot thing as the reason to move to rainy country from sun country USA. lol
 
I will check out the commute times see if it is feasible..........
 
ok guys, thank you all very much for the replies :-) I have learned a lot about how the cooling system works in BMWs :-) however, I do understand the basics of cooling systems and I think I have wound up with too much information here :-)
I will revert back to my initial questions so we can keep it simple and hopefully I can get this problem sorted :-)
1. I am now thinking that the car overheated because the clutch on the fan did not engage, can the switch on the rad cause this?
2. where is the switch on the fan? I presume at the bottom where the water release valve is, yes?
again, thank you all for the help and science :-)
 
The fan is mechanical on the M44:

image.webp

If you have aircon you will also have an electric fan:

image.webp
 
if your car has aircon , it will have an additional electric cooling fan, or if someone has added one, in stock none aircon form the M44 has a viscous fan only, and there are no electrical connections (switch, sensor etc).

I think you have just been unlucky with your thermostat Dave.
 
zedonist said:
if your car has aircon , it will have an additional electric cooling fan...
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That's for the UK. In the US, the 1.9s all got air conditioning and only one fan, the electric fan mounted on the back of the radiator. No viscous fan.
 
vintage42 said:
That's for the UK. In the US, the 1.9s all got air conditioning and only one fan, the electric fan mounted on the back of the radiator. No viscous fan.
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Hence why i provided my answer, Unless County Kildare is the 51st State of America Dave will have a viscous fan as standard.........
 
Fingers crossed for you David.
The original 1.9L engine in my Z3 had a pitted and warped head. (I've had this welded and skimmed but now seeing normal 200psi on cylinders 2,3and 4 but zero on 1.....I've just posted this on this website.
The second engine also has a warped head and this needs skimming due to overheating.
Joey (fellow Zroadster member and now a good friend) had the same problem and we removed his head had it skimmed and refitted it.
In both cases a very experienced mechanic connected his pressure tester to the radiator filler and let the engine run after thoroughly bleeding the system. After a fairly short time (engine hot) the pressure increased rapidly due to cylinder pressure entering the cooling system. His diagnosis was warped head.
Are Joey and myself just unlucky or is there a widely recognised M44 cooling problem?
 
The M44 is a pretty robust engine Barry, it was developed from the M42 and both have been successful race engines, I think the problem comes with age, neglect by previous owners and general wear and tear.

If the coolant system is looked after correctly, there should be no ill effects such as over heating, and it is over heating that causes the head to warp, crack etc, I would say you have been unlucky.

It is important with alloy heads that the coolant has an inhibitor to prevent corrosion products forming, it's very much like a heart attack caused by furring of the arteries, in an alloy head the galleries become furred up, and then it's choking time.

The benefits of the M44 is that it has a forged crank, timing chain rather than a belt, a tubular exhaust and variable intake which makes it a very robust and nicely tuned DOHC, one of the best in its time period, similar to the Ford BD series, it's this development that allows it to take a supercharger with out internal modification and not break.

I know it's frustrating,but once sorted, I am sure you will enjoy it.
 
Eastwood in the USA sells a set of brushes for cleaning cooling passages and as Zedonist says there is a lot of blockage within the head passages as they are fairly small and roughage accumulates in some of the tight turns within. I Am not that familiar with the aluminium heads but iron heads are soaked in a bath of a caustic solution overnight and pressure washed before rebuilding and skimming. Perhaps you can try clearing your head's passages prior to install. I've even used air pressure in the past with good results. HTH JIM
 
zedonist said:
Plus does moving to Seattle improve cooling in a Z3, may have to try it.........
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I would wait a bit Rich, at least until Jim lets you know how a Z moving to Canada affects the cooling first.
ps. It ain't snowed yet! ;)
 
So far so good guys!! Cooling won't be the problem in Washington State but visibility may now that pot is legal to smoke and purchase. Planes now fly around it stating it was like flying over Mt. St. Helens all over again. But I think Zedonist just might be okay there as fast food rest. Are everywhere. Probably gain a few lbs. so milage would drop but who'd care? Spark me up!! JIM
 
ok guys, thanks for the info, so I don't have a switch to worry about, it must have just been a stuck stat. I have been driving it still for the past week and it hasn't overheated again, even in traffic so I am pretty sure the head is ok :-) I will just fit a new stat again and check the viscous fan that that is working ok and the coil in the centre is free moving
thanks again and as per usual, I will post when I have it sorted :-)
 
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