Engine overheating

[Paul DomoneyParticipant]

After an extended rebuild of my 1952 Lt 15 we are finally on the road. However I am worried about the overheating. The engine has been overhauled and the radiator also re cored. As far as I can tell the water pump works efficiently.  So what might be the cause of overheating? Could it be timing? Any ideas would be most welcome.

[BernieParticipant]

Paul,

Yes, it could be timing but I wonder to what extent was the engine overhauled?

Were the liners removed and the block cleaned out?  It is very common for these engines to silt up and, when an engine has stood for a long time the deposits can solidify like concrete.  This will considerably reduce the effective volume of the waterjacket as well as hindering coolant flow.  Try removing the drain plug on the left of the block.  If coolant does not flow very freely there is almost certainly a build up of silt in the block.

Were the waterways in the head checked?  Inside the head there is (or should be) a steel tube designed to direct coolant flow over specific hot spots.  When the tube corrodes it can become blocked and the head will overheat as a result.  Replacement tubes are available but, personally, I found the engine of my Légėre ran very well, at even the highest ambient temperature, without the tube at all.

B…….

[David FaulknerParticipant]

One other thing to check, is the fan fitted the correct way around so it’s pulling maximum airflow i.e. the ‘concave’ face should be toward the engine.

It’s a simple thing to check.

[Paul DomoneyParticipant]

Hi. David and Bernie

Thanks for your advice. The short answer is that I do not know if the water jacket was checked during the overhaul.  I have to assume that it was but there is no way of knowing. And finding out would seem to be quite an exercise. I think the fan is installed correctly.  I took a photo but do not know how to transfer it onto the forum. So I have someone here today who can check the timing and if that does not solve the problem the next step is to take out the drain plug as you suggest. After that the only answer is to remove the head and clear the water jacket. Not something that I would want to do but needs must.

Thanks for your input.  Much appreciated.  I will let you know in due course whether or not I have succeeded.

Paul

 

 

[BernieParticipant]

Paul,

Fingers crossed it is just timing.

If you do need to inspect & clear the water jacket I fear it will entail more than simply removing the head.  Decent access is really only possible if the liners are removed by which time the job is becoming major.

Unfortunately, proprietary items designed to clear systems of accumulated crud are rarely able to shift the solid mass that tends to form in these blocks and it can literally be a job for a chisel.

B…

[Paul DomoneyParticipant]

OK. The good news is that the fan is installed correctly; bad news is that when we removed the drain plug as you suggested, hardly any water came out so we have to assume that the water jacket is silted up. Now I am reluctant to take out the engine so we are going to take off the head and see how far we get in cleaning out the water jacket and the head. Do you have any comments on this course of action?

Thanks again for your input

Paul

 

[BernieParticipant]

Paul,

I understand your reluctance to remove the engine but, in my experience, you will struggle to see, let alone clear, the problem.  I believe the liners will need to come out and that means removing the pistons from the crank.

However, working from on top as you intend, the  most important thing will be to ensure you do not disturb the liners.  They are simply sitting in place in the block and, without the head to restrain them, they are free to move.

Once the head is off, do not turn the engine over unless the four pots have all been clamped down to prevent them being lifted by the pistons.  This can be achieved by clamping it with washers or similar, see this post on the 6 cyl page :

https://traction-owners.co.uk/forums/topic/welcome-to-the-dedicated-6-area-of-the-forum/#post-26392

If the silting is as bad as I think it could be, it may initially anchor the sleeves but do not rely on it because once the joint between a liner and the block is disturbed it nearly always results in the need to replace the liner gasket and, if that happens, you will almost certainly have to strip the lot down.

B….

[Peter FeredayParticipant]

What happened about the timing check – was it ok?

Just for the record I removed the block drain plug on my 11B a few years ago to try and drain the block. Absolutely nothing came out and I could not shift anything by inserting a small drill bit; whatever was blocking it was rock solid. So I gave up at the time, BUT my engine did not overheat. If there is some coolant coming out on yours it is not totally blocked and so there may be another cause – timing, water pump or a radiator that hasn’t been re-cored properly. Presumably no thermostat fitted? Mine has an in-hose thermostat and if that failed shut it would block everything. With the engine running and up to temperature can you see water circulating through the top of radiator with the cap removed? Taking CARE of course as temp builds up.

My engine was rebuilt a  couple of years ago with new pistons and liners. All the silt was removed in the block and coolant now runs freely from the drain plug when removed. However it still seems to run at the same temperature as before.

 

Peter

[Paul DomoneyParticipant]

Hi Peter. Very little coolant came out which clearly points to that as being the prime cause of overheating. Have not re-checked the timing yet and it is possible that might contribute but the engine does run beautifully. Yes coolant circulating nicely at top of radiator which has been re-cored and water pump has also been checked. No thermostat fitted.

So I think that I am going to take off the head as a first step but I take the point that in the end I may have to strip the engine.

Oh well, what else can one do with spare time provided by Covid 19?

I expect that you all realized that mine is a Slough built Lt 15. What you may not know is that I live in Zimbabwe!

Many thanks

Paul

 

[BernieParticipant]

In that case..

Rombo rakanaka.

B……..

[Paul DomoneyParticipant]

Tatenda Baba.

[Norman AndersonParticipant]

Ndino kuzivo……

[BernieParticipant]

Hapana chandinoziva

B…….

[Paul DomoneyParticipant]

So we took off the head and it was not as bad as we thought it might be and certainly we have dislodged all the muck in the block and the head. I also returned the radiator to the chap who said that he had cleaned it out and repaired the leaks which he clearly had not done!

So next week we will re assemble the motor and try again. Luckily I have a full set of gaskets so it will have a new head and manifold gasket.

[BernieParticipant]

Progress indeed, fingers crossed at this end.

B……..

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