Club 80-90 Forums

I've just fitted and fired up my new engine (1.9dg) for the first time. The engine runs sweet but for some reason water doesn't seem to be getting to my radiator. I have tried bleeding the system as per the wiki but the radiator remains cold. In the end I turned the engine off as the temperature gauge kept rising and I didn't want to risk cooking my new engine. I have taken out the thermostat to make sure it works (by putting it in hot water) and it is expanding as it should. The blower in the cab is hot so it makes no sense to me

Am I missing something obvious????

Any help would be gratefully received

early or late cooling system?
Opened the bleed screw in the engine bay?

It may not be overheating it may be air/steam around the sensor.
In this weather it will take quite some time for the stat to open, the bleed screw allows the air to pass out of the rad until such time.

How long did you run it?

Its a late system. I had the bleed screw on the stat open. I run it for about 20 mins but the needle on the temperature gauge starting rising well over half way so I stoped

I think you need to make sure it's full of coolant and try again, the system runs hotter when it's not pressurised, it won't be pressurised until all the air is out which won't happen until the stat is open and it's properly up to temperature.


It's normal for the guage to get to 3/4 before rad kicks in so unless it goes over 3/4 stick with it, bets to have it running at 2000RPM to get the pump working so stick a brick on the throttle.

You can tell if the stat is open because the as it warms up you can reach through past the bulkhead and feel the rad return pipe which connects above the stat, if it's cold the stat isn't open, as the stat starts to open it gets warm then hot.

I assume it was OK before you changed the engine so unlikely RAD is blocked, assume pump is spinning as heater is getting hot.

As far as I know the cooling system was fine. When I rev the engine water comes out the radiator bleed valve so I'm assuming there is no block. What I can't get my head around is that there is no water getting past the thermostat but cold water comes out the rad. To be honest I've spent a small fortune on a new engine (along with a lot of time) so perhaps I'm being a bit precious with it. I'll start it up again this evening and let it run a bit longer. Thanks again for your help

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Colant flows other way from how you are thinking
thermostat is at the end of the loop, rad in the middle, pump at the start

thermostat opens when the coolant below it reaches the right temp.

Certainly helps to get the front end higher than the back, and don't be afraid to give it some revs like itchyfeet says. Follow the wicki but it maybe takes more time than you imagine to bleed the whole system.

Well this is rather embarrassing. It looks like I had the thermostat fitted the wrong way round . I guess it's all a learning curve!!

However, my next issue is this.... when I flip the thermostat around so it it the right way the top part of the thermostat housing doesn't fit. There is a gap of about 5mm around the joint between the lower and upper part of the thermostat housing. It seems to be sat as it should in the lower part.

You haven't put two O rings in have you?
( And the spring bit should point down ward. )

Smiffo wrote:You haven't put two O rings in have you?
( And the spring bit should point down ward. )

Nope just the one. Although the gap is about what I would imagine it would be if there were two.

Probably best to post a picture up, so people can see.

I am assuming there is nothing obvious caught, or the thermostat housing isn't distorted in shape?
Seems odd that it did fit upside down, but won't fit the right way up now...

Might be an idea to boil some water and make sure the thermostat actually opens and closes too...?

I've got it sorted now. I'm not having much luck. It turns out the 'U' shaped clamp on the underside is slightly too wide so the thermostat will not sir correctly in the housing. I think this is why I had it up side down as it only appeared to fit one way. I'm now off to heritage to get a new one so fingers crossed I shall be back on the road very soon

You must have had a stat in there before? don't you still have that one?