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Technical MK2 Turbo - Thermostat woes

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Technical MK2 Turbo - Thermostat woes

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fokker

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Hi all - I live in New Zealand and drive a 1991 mk2 uno turbo (1.4 engine).

A while ago, the engine overheated and subsequently warped the head. I have had this fixed and the engine is back together and running, but still overheating. The top radiator hose is hot while the bottom hose is cold - this would surely indicate a faulty (stuck closed) thermostat, correct?

The thermostat seems to be of an unusual type where it is all contained within a sealed housing, so I'm guessing I need to replace this whole unit, is this the case? Either way, I am having a very hard time finding a replacement unit, it seems that nobody in NZ stocks the correct thermostat. I have been advised that one from an uno 70 should fit, with the addition of a tapped hole for a temp sensor. Can anybody confirm this?


Also, I have a water leak coming from the back of the engine. It's almost impossible to see where it is actually coming from when the engine is running, and it doesn't leak when the engine is off, which makes it hard. It appeared to be coming from the frost plugs, but I replaced these and it didn't make any difference. I'm guessing it is coming from somewhere else and running down to where the frost plugs before dripping off. The only thing I can think of is if it is leaking from the thermostat housing where we didn't fit a gasket yet, but it seems kind of unlikely. Are there any known locations of common water leaks? I'm really hoping that the block isn't cracked or something annoying like that :confused:

Please help :eek:
 
Hi,

Mal Simmonds is your man. (Dino Enterprises) could still be on holiday, was last week.

He will have what you want and is full of advice.

google is your friend.

Not sure about where your leak is coming from my Unos are early lampredi engines.
 
Welcome to the forum :wave:
As you can see, there are other Kiwis here too.

Later 1.4 engine is very similar to earlier 1.3, so same leak locations apply :) You have the water pump back there, with the steel pipe that can rust through. Quite often the leak is a tiny split in a heater hose or something like that. On mine, the offending heater hose had 'Nissan' moulded into it.

I know for the 1.3 (1299/1301cc) it is possible to drill and tap a hole in the 70 thermostat and then it fits the Turbo, as you said. But, I'm not 100% sure that applies to the 1.4 (1372cc). I also know that the thermostat is different for some of the later engines such as for the Tipo 1372cc - it has one less hose outlet.

So if you do a visual inspection of yours to note the location and angle of the hoses, and then find a thermostat for an Uno 70, you should be able to see pretty quickly whether it will interchange (sorry I don't know for certain!)

-Alex
 
fokker said:
I have been advised that one from an uno 70 should fit, with the addition of a tapped hole for a temp sensor. Can anybody confirm this?
Click to expand...

Yes

fokker said:
Also, I have a water leak coming from the back of the engine. It's almost impossible to see where it is actually coming from when the engine is running, and it doesn't leak when the engine is off, which makes it hard. It appeared to be coming from the frost plugs, but I replaced these and it didn't make any difference. I'm guessing it is coming from somewhere else and running down to where the frost plugs before dripping off. The only thing I can think of is if it is leaking from the thermostat housing where we didn't fit a gasket yet, but it seems kind of unlikely. Are there any known locations of common water leaks? I'm really hoping that the block isn't cracked or something annoying like that :confused:

Please help :eek:
Click to expand...

You need to pressurise the cooling system and then check for the leak. The engine block can develop cracks between the frost plugs on the rear of the block. If so the block is stuffed.

Who fixed the head for you in the end?
 
It wouldn't surprise me if this turns out to be YOUR 1991 Mk2 Uno Turbo, Steve... it seems to have passed through a succession of owners since you left NZ, and how many '91 Uno Turbos are there anyway... ;)

fokker said:
A while ago, the engine overheated and subsequently warped the head. I have had this fixed and the engine is back together and running, but still overheating. The top radiator hose is hot while the bottom hose is cold - this would surely indicate a faulty (stuck closed) thermostat, correct?
Click to expand...

And sorry, I missed that the first time - to me, that suggests a blocked radiator or a lack of circulation through the whole system (water pump?) If the thermostat is closed, the top radiator hose should hardly get warm at all.

What was the state of the coolant before the overheating? If it was rusty brown, then it's worth taking the radiator out and back-flushing it. It's hard to know what has happened in the past.

It is really rare for these thermostats to stick closed. They usually fail in the open position. Therefore, if you suspect it is stuck closed, I think you should remove it and boil it in a saucepan (you can clean the saucepan before you use it later), and you should see it open (then hopefully, close).

It's summer here, so is the radiator electric fan working correctly? If not, you would expect the engine to overheat when stuck in traffic after a run.

That's about all you can do really - work through methodically, inspecting and testing each component. Since you have had someone else fix the head, I think you should also be taking the car back to them for their opinion on the water leak problem. They may not be responsible, but at least they will know a bit more about your particular car than we do :)

-Alex
 
Last edited:
SteveNZ said:
Yes



You need to pressurise the cooling system and then check for the leak. The engine block can develop cracks between the frost plugs on the rear of the block. If so the block is stuffed.

Who fixed the head for you in the end?
Click to expand...

I don't like the sound of the that... if the block is cracked I will probably cry :cry:

I'm not actually sure the name of who it was that fixed the head, I got it done at mates rates through a mechanic friend. It was a head specialist in Hamilton but the name escapes me.



alexGS said:
It wouldn't surprise me if this turns out to be YOUR 1991 Mk2 Uno Turbo, Steve... it seems to have passed through a succession of owners since you left NZ, and how many '91 Uno Turbos are there anyway... ;)



And sorry, I missed that the first time - to me, that suggests a blocked radiator or a lack of circulation through the whole system (water pump?) If the thermostat is closed, the top radiator hose should hardly get warm at all.
Click to expand...
Those were my first thoughts when it first overheated. When I had the engine apart I had a look at the radiator, I was able to run water from a hose freely through it so I think it's okay.



alexGS said:
What was the state of the coolant before the overheating? If it was rusty brown, then it's worth taking the radiator out and back-flushing it. It's hard to know what has happened in the past.

It is really rare for these thermostats to stick closed. They usually fail in the open position. Therefore, if you suspect it is stuck closed, I think you should remove it and boil it in a saucepan (you can clean the saucepan before you use it later), and you should see it open (then hopefully, close).
Click to expand...

I think the coolant was a bit brown when it first overheated, but that was like 9 months ago now so it's getting hard to remember stuff like that :( that's how long I've had the thing sitting in my garage.
I did the thermostat test, twice now. Once at a Caltex station when it first started overheating (this was while we were moving from christchurch to taupo that it happened), and once since. Because of the design of the thermostat it is pretty hard to see when it is open and closed, and if it is opening and closing the whole way. When we took it out at the caltex station we tried to jam it in the open position but it didn't seem to make any difference to the overheating.

alexGS said:
It's summer here, so is the radiator electric fan working correctly? If not, you would expect the engine to overheat when stuck in traffic after a run.

That's about all you can do really - work through methodically, inspecting and testing each component. Since you have had someone else fix the head, I think you should also be taking the car back to them for their opinion on the water leak problem. They may not be responsible, but at least they will know a bit more about your particular car than we do :)

-Alex
Click to expand...

The electric fan did stop working around the same time, but I
suspect this is more of a symptom rather than a cause - it happened during open road driving so the fan shouldn't make any difference. I assume that the cold water in the bottom part of the radiator is where the thermal switch for the fans is located, hence their not working.

I am reasonably sure that the water pump is working, water seems to be flowing in and out of the radiator fill bottle. At this stage I don't know what else it could possibly be?


On an unrelated note, anybody want to buy a '91 uno turbo? :p
 
alexGS said:
It wouldn't surprise me if this turns out to be YOUR 1991 Mk2 Uno Turbo, Steve... it seems to have passed through a succession of owners since you left NZ, and how many '91 Uno Turbos are there anyway... ;)
Click to expand...

Both my Mk2's were 1990 models, the red one is always on Trademe. Its got a blown head gasket now apparently.

This is the one Nova use to own, it use to have all the blue LED's. I remember you looked at it once and the gearbox mount broke.

There really cant be many left because its the same ones that keep turning up on these forums.
 
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