Diesel cooling system problems

Gazza36 said:

Rather than start a new thread i thought it would be ok to add a new problem with a new car to this one?

Car ran fine until changing coolant.
Now overheats.
Brand new oem fan locks on cold start then loosens off but doesnt lock when overheating.
Header tank bubbles over sometimes even before it overheats if cap is off or pressurises a lot if cap on.
Stat seems to open.
Heater blows cold.
Cylinder leakdown and coolant static tests ok, dynamic coolant test eventually goes over 7 psi once it starts overheating.

Any help appreciated and sorry to go over old ground but i am stuck, cheers.

P. S. Water pump seems ok, metal impeller as well.

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You either have the mother of all airlocks or a cracked head. If you fit a static test rig it should show 5 to 7 Psi at normal temp. Heater should be the first thing to get warm. Have you checked the stat? Try back flushing heater.

Gazza36 said:

Brand new oem fan locks on cold start then loosens off but doesn't lock when overheating.

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Why not? You haven't bust the new fan fitting it?

Is this the petrol? The petrol can be an absolute sod to get all the air out.

Grrrrrr said:

Why not? You haven't bust the new fan fitting it?

Is this the petrol? The petrol can be an absolute sod to get all the air out.

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Check thread title my good man.....

Saint.V8 said:

Check thread title my good man.....

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Oh yeah, valid point!

Gazza36 said:

Ok so still having this issue, had to be recovered again, this time to the garage where the car is now. They are a bit mystified, a sniff test showed nothing and on a test drive the temperature was fine until the end when the gauge shot up, they suspect the sensor but it's still pushing coolant out of the overflow, now if the system isn't pressurising why is it doing this, I cannot understand. Now the fan could account for any overheating or the sensor but what about this overflow? Many thanks, Gary.

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If it's blowing out coolant and the fan is OK, sounds like a cracked head unless the expansion tank cap is faulty and not holding pressure.

Did you check the thermostat opened before fitting it, also check post #31

I cant see how if ihave broken the fan, i hope not. Flushed the heater both ways, I might put a new stat in to rule it out, cheers.

Gazza36 said:

I cant see how if ihave broken the fan, i hope not. Flushed the heater both ways, I might put a new stat in to rule it out, cheers.

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Make sure you test it before fitting ,in a pan of hot water and that it has an air bleed hole that must be fitted at the 12 o clock position ,see Rave.

Gazza36 said:

I cant see how if ihave broken the fan, i hope not. Flushed the heater both ways, I might put a new stat in to rule it out, cheers.

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I think @wammers said there was a way once.

Grrrrrr said:

I think @wammers said there was a way once.

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Not me the fan either works or it doesn't. Should run relatively freely until the air in the shroud overheats the viscous unit and opens the viscous fluid valve. Centrifugal force then sends fluid to outer part of viscous unit causing it to be driven. It should never spin at more than 80% of engine speed. Under normal driving conditions the fan is not engaged and the engine is cooled by ram air. Only when car slows or stops in traffic should the fan be engaged to get rid of latent heat from the engine. Think this bloke has a big airlock. Heater should be the first thing to get warm, as coolant is circulated out of the block through the back of the head and through the heater, back along the heater outlet pipe on the O/S of the head and back to the pump. Only when the stat opens is coolant run through the rad. If anyone has trouble after draining rad and block to change coolant. My advice would be to remove top inlet hose from rad (the R/H one looking from the front). Use a length of hose to fill the rad and fill the block through the disconnected top hose. At some point you will see coolant rising in header tank.You will have no end of trouble trying to fill and bleed the block if the stat does not have a bleed hole in it. Also make sure the bleed tube to the tank is clear of all coolant.

So if it is a brand new fan and it doesn't lock up it isn't getting hot?

Took the stat out and put it in some hot water and it opened up alright, the fan did not lock up on cold start so i am sure now that it is pooped. I had a carlton years ago where someone had removed the viscous fan and replaced it with an electric kenlowe one, is there one available for this engine because these viscous ones seem to be temperamental.

Just seen wammers reply so i think i will refil that way and maybe that will prevent an airlock.

Gazza36 said:

Took the stat out and put it in some hot water and it opened up alright, the fan did not lock up on cold start so i am sure now that it is pooped. I had a carlton years ago where someone had removed the viscous fan and replaced it with an electric kenlowe one, is there one available for this engine because these viscous ones seem to be temperamental.

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Datatek has a mod using the aircon fans.

Gazza36 said:

Took the stat out and put it in some hot water and it opened up alright, the fan did not lock up on cold start so i am sure now that it is pooped. I had a carlton years ago where someone had removed the viscous fan and replaced it with an electric kenlowe one, is there one available for this engine because these viscous ones seem to be temperamental.

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There are 2 good electric fans already there if the car has aircon, they cope happily cooling with the viscous removed

A very cheap and wise thing to do is to check if you have any combustion gases in the cooling system. Had the same symptoms in my car. I went thru all the different changing of rad, stat, fan etc. and even went to the stealer to have a coolant check with negative result. (the stealer did not understand how a CO2 test worked).
Then i bought one like this: https://www.ebay.com/itm/BT-3-BLOCK...979883&hash=item3f9eb34cb9:g:MuUAAOSwLEtYi8Gi
-and in no time I had the verdict: leaking of combustion gases into the coolant.
The head was ok, but the 1. year old HG had a tiny crack 10 mm from a water channel.
Just be sure to read the instruction for the set. Petrol makes the fluid turn yellow while diesel makes the fluid go green.
Also remember to block the leak pipe in the expansion tank neck to get the gases go into the fluid.

Just wish i had done this test months before....

So far so good, filled the rad up and then the rest of the system through the passenger side hose going to the head and all seems to be ok. When the stat opened it spat a load of coolant out of rhe over flow pipe on the top of the header tank and the coolant rose up into the funnel, switched off, topped up, restarted and so far so good.
I haven't been able to get it hot enoughyet to get the fan working but it did lock up on start so i am hoping it is ok, many thanks.