The Triumph Dolomite Club - Discussion Forum

My Sprint has a coolant system problem, as a result I have taken the head off. In other thread posters have suggested checking the water pump.

I have the pump cover off and have turned the engine over by hand. The pump turns smoothly and I can see no evidence of leaking from the slot. What other checks should I perform while I have access? (6 vane pump)

Is the pump the origianl pump and original cover or did you get a new one when you rebuilt the engine? I ask as there was a discussion over on the Stag forum a while back over different profile impellers and their fit against the top cover. Basically there seem to be some "long nosed" ones about that if used leave a large gap between the impeller vanes and the cover making the pump pretty ineffective and giving rise to the symptoms you described in some of your other posts about over heating.

This is the link to the thread on that forum - I think you should be able to view it, if not let me know and I'll cut and paste the relevant bits.

https://www.socforum.com/forum/forum/st ... tion-again

Post #6 and #17 have pictures (worth a thousand words, so they say )

With regard to checking your pump, if it turns OK and the gear is meshing correctly the only other thing to check is that the impeller splines do fit tightly on the shaft. Basically try to turn the impeller with your fingers. If it does not move and feels tight it is OK. So that just leaves checking that the cover matches the impeller with minimal clearance. You can verify this by spreading a layer of putty or blu tack over the inside of the cover and refitting, then remove it and examine the impression made by the impeller.

Roger

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1975 Sprint Man O/D in Honeysuckle Yellow
1971 Stag Auto White

Too many cars, too little time!

It is the original pump rebuilt. Alas I did it, so the work could be suspect. What worries me is the seal between the impeller and the rest of the pump. I didn't have the impeller machined flat, which could have been an error.

The slew gear is the original one and was in good nick.

If there is no leak from the slot in the cylinder block the seal is seated correctly on the back of the impeller.
Yes, well done !
Just to give you a yard-stick, when CWL stripped the water pump / jackshaft gears I could drive 1 mile to the supermarket, load up and drive 1 mile back. At which point the water temp; gauge would be up at 3/4 with bloop-bloop noises coming from the header tank. The water pump impeller would turn by hand with a "tink-tink" noise from the remains of the gears I found later.
The Sprint does run hot very quickly if the water pump is not turning.
HTH,
Tony.

As Tony says if there is no leak then the seal is fine. The impeller only needs skimming if it is rough. Good choice to refurb your old pump and keep the original gear. As long as the impeller is tight on the splines it should fine.

Whilst you have it apart it is worth checking the impeller to cover clearance, just for your piece of mind.

Roger

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1975 Sprint Man O/D in Honeysuckle Yellow
1971 Stag Auto White

Too many cars, too little time!

The late great Jon Tilson wrote an article on the water pump which can be found in the "members only" section.

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Toledo Man

West Yorkshire Area Organiser & forum moderator
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Modelling clay, screw it down and measure the thickness of the clay?

Just out of interest, why would too much clearance be bad?

The bigger the clearance the less efficient the pump is at circulating the water. At its extreme it would be like the impeller spinning in a large tank, not a lot would happen apart from a bit of cavitation. This is why when refitting the cover you have to check the clearance and get the correct thickness gaskets to the nearest 10 thou to give a tight running clearance. If it wasn't important they wouldn't have bothered with the faff of different thickness gaskets. I assume you did refit the cover as specified in the Repair Operations Manual and select gaskets to give the correct running clearance?

Roger

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1975 Sprint Man O/D in Honeysuckle Yellow
1971 Stag Auto White

Too many cars, too little time!

The waterpump impeller is the same as all other aitomotive waterpumps. Do you check the play also when fitting for example a 1300/1500 waterpump or the one for your classic mini?

In 95% you are adjusting the play between the bolt and the cover. Not the actual impeller scoops and its seat. Adjusting is a bit overrated and doesn't affect the working. I don't bother and fit always the thickest gasket.

Jeroen

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True, I had not thought of it in those terms. I suppose I was just following the ROM and also the fact that there are different impellers around (6/12 vane for example) and these need to match the cover. My original post was really to check the cover did match the impeller, which if it was the original pump but just rebuilt it should. No harm in double checking whilst it is apart.

Roger

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1975 Sprint Man O/D in Honeysuckle Yellow
1971 Stag Auto White

Too many cars, too little time!

The pump is the next job, once the gaskets arrive.

Putting the head back on was non too fun. Thanks to the angle of the engine, I found you couldn't fit the studs to locate the gasket and the lower the head on them. In the end I held the head above the block, with the exhaust manifold attached. While my father located the gasket and inserted couple of the studs.

There must be a better way, the head is not light when you have to hold it in position like that.

Did you get to the bottom of your over heating issue?

Hi Tony,
I have just become the owner of a Dolomite Sprint and it is presenting theses symptoms also.
after running for 15mins on low idle the engine appears to be very hot.
With an infrared temp sensor gun I am measuring temps of 110c at the thermostat housing and 46c>.53c at the outlet of the water pump, where the bottom rad hose is connected.
When I stop the engine it starts to "bloop, bloop" in the expansion bottle and will also spit some coolant out for a a couple of seconds
Could this be a circulation issue ??

Firstly, welcome to the forum.


I suggest you start with the thermostat……


Ian

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Welcome on here and congratulations on choosing one of the range of the best classics.
Since the car is a recent acquisition, the first thing I would ask is ...

Was it the previous owner's daily driver or was it a museum piece ?
( The point being that a museum piece will not have been run regularly and the cooling system may be coked up.).

What is the antifreeze like in the thermostat outlet when cold.
( If it is a nice translucent blue that is good. If rusty that is bad news. )

Has the previous owner used waterless coolant ?
( If so then yes, it will run hotter.)

A drain and refill of the antifreeze may be a good idea anyway. Check the drain plug on the nearside of the block. This is likely to be gunged up. No downside to this.

If you do decide to change the thermostat, ensure it is the correct one with the extending foot at the base so it closes off the bypass port when hot. And while you are at it, check the small drilling in the thermostat outlet top is clear ( it goes to the water hose at the top of the rad; and acts as an air bleed to this point. )

Some other questions.....

Does the heater work ?
Is the IGN timing O.K. ( I note you have been running at idle when there is not much advance. If it's very retarded it will run hot.)
Does the dashboard temp gauge work and what does it read at various stages ?
Does the service record indicate that the rad; has been reversed flushed through recently ?
Again, is the engine running on a very weak mixture at idle ? This will also make it run hot.

Again I've never been a fan of those I.R. temp sensing guns unless they are used with an electronic thermometer first to determine the error as the emissivity of the surface will affect the reading.
I think the first thing would be to verify the water is actually running hot with an electronic thermometer and use the in dash temp; gauge for subsequent measurements.

Lots of questions I'm afraid.
Good luck with it,
Tony.