Perkins 4108 coolant flow problem

[pcatterall]

My refurbished 4108 is up and running ( in the garage). I have installed some 'raw water plumbing' so I can do a proper test.
There is an overheating issue as follows. The coolant water gauge climbs rapidly towards the 100 degree mark but the raw water coolant is not getting even warm.
Water in the header tank is getting very hot but not flowing through the heat exchanger jacket.
I had installed a new hot water 'valve' and actually checked that it was opening as required.
It would seem that the coolant water is simply not being pumped around the system. I am going to give it some though but am minded to remove the header tank and check the valve ( possibly I will try running the engine without it first.
Thought I would give the experts a 'call' first to see if I am missing anything obvious?

 

[RichardS]

I assume that the hot water valve is the thermostat? That would be my first thought but as it's new then it should be fine, assuming that it's the correct heat range.

My second thought would be that the impeller in the water circulation pump, assuming this engine has one, is spinning on its shaft and not actually pushing any water around.

Richard

 

[Dave_Seager]

The fresh water pump is usually driven from the alternator belt. Do you have this fitted?

 

[VicS]

I assume that the hot water valve is the thermostat? That would be my first thought but as it's new then it should be fine, assuming that it's the correct heat range.

My second thought would be that the impeller in the water circulation pump, assuming this engine has one, is spinning on its shaft and not actually pushing any water around.

Richard

Regarding your second thought and the fact that I have an overheating problem , not yet investigated, with one of the cars It was suggested to me, by my MOT tester, that the impeller of the coolant pump could be corroded ... like a sacrificial anode !

Anything you've come across ? Could, of course, be spinning on the shaft

Obviously will check the thermostat and give the rad a good flush but I am reluctant to disturb the water pump without good reason.

 

[lw395]

Is the block warming up or just the head?
Have you checked the head is actually getting hot?
Sounds like either faulty thermostat or coolant impeller not spinning?

But if the raw water is flowing through the heat exchanger, why is that so much colder than the header tank? Airlock?

If the head is not getting hot, then the thermostat will remain closed and the header tank and HE will be heated by the exhaust.
Can happen, idling at zero load!

 

[VicS]

Is the block warming up or just the head?
Have you checked the head is actually getting hot?
Sounds like either faulty thermostat or coolant impeller not spinning?

But if the raw water is flowing through the heat exchanger, why is that so much colder than the header tank? Airlock?

If the head is not getting hot, then the thermostat will remain closed and the header tank and HE will be heated by the exhaust.
Can happen, idling at zero load!

There is a note in the mnaual for the 4.108 which says to make sure the correct type of thermostat is fitted. "Certain engine applications have an external bypass which incorporates a thermostat with a bypass blanking valve. This valve closes the bypass port as the thermostat opens ."

 

[RichardS]

Regarding your second thought and the fact that I have an overheating problem , not yet investigated, with one of the cars It was suggested to me, by my MOT tester, that the impeller of the coolant pump could be corroded ... like a sacrificial anode !

Anything you've come across ? Could, of course, be spinning on the shaft

Obviously will check the thermostat and give the rad a good flush but I am reluctant to disturb the water pump without good reason.

The only similar thing I have direct experience of is a plastic impeller slipping on the shaft although I would guess that the OP has a metal impeller and I've never had any problem with those although I have read about it happening with metal impellers.

However, in a situation with a thermostat definitely working, or perhaps even removed entirely, if the block is getting hot and the temp gauge is registering but the top inlet hose to the radiator/radiator matrix still feels cool it's difficult to think of any other possibility other than the pump failing to circulate the water.

Richard

 

[pcatterall]

Thanks all. Yes, by valve I did mean thermostat (senior moment!) The fan belt is in place and the pulley turning. I propose to try again but will more carefully feel which components are getting hot and report back.
Just looking at my set up again: the coolant is in the header tank at the front of the engine and directly connected to the heat exchanger at the back and returns via the exhaust manifold. I can confirm that the exchanger and the manifold are clear so why are they not getting as hot as the water in the header tank? are senior moments at work again?

 

[AndrewB]

When my 4108 had this problem it turned out that the manifold had corroded internally, on a heat-exchange system, dumping rusty sludge through the cooling passages in the engine block and preventing the coolant flowing freely. (Also it meant that raw salt water was flowing through the engine). I managed to flush it clean by first removing the outlet plug and rigging my dinghy pump to blow into the system, then turning the engine over with the plug still out, continually adding fresh cooling water. But I was lucky, any more blocked and this wouldn't have worked.

That having been said, there are numerous other possible reasons for your problem, as previous replies suggest.

 

[pcatterall]

A BUMP up on this one please!!
Many thanks for the responses to date. I have been waiting delivery of a remote heat tester ( the gun type) so that I can get real figures on what is going on with the plumbing.
I now have the gun, it will go into my boat tool kit as I can see it could be quite useful.
I propose to do some more testing and will value any advice.
As stated the 'raw water' plumbing is circulating water well though it is not getting water. The heat exchanger and manifold were all checked for water flow. The header tank is full and there are no internal or external leaks from that. The fresh water pump has been off and looked fine and the belt is in place.
when running and despite the raw water coolant remaining cool the water temp from the head sensor is getting hot quickly as is the water in the header. By hand I could not detect any real heat in the pipes on the header-exchanger-manifold 'circuit' ( I am not sure just what should push water round this 'circuit'.) also I am not sure if the block was getting warm.

I assume that on start up the thermostat will be closed so the 'circuit' above will not be required, then as the water in the block and head warms up the thermostat will open and the water in the header 'circuit' can start to flow?

I propose to run the engine up again, switch off when it gets too hot and record the temps at the header, outer of exchanger, manifold, block, head and for good measure the oil filter.

Any advice on the general situation and on testing will be welcome.

This engine is identical to the one installed on board and this exercise has been very instructive ( and the advice invaluable!)

 

[Billjratt]

My 4108 has two plugs with squares on top for a spanner, one on the head near the bellhousing end and the other on the exhaust manifold. They are to clear airlocks in the freshwater system. Have you loosened them and topped up the header?

 

[pcatterall]

My 4108 has two plugs with squares on top for a spanner, one on the head near the bellhousing end and the other on the exhaust manifold. They are to clear airlocks in the freshwater system. Have you loosened them and topped up the header?

Thanks for that.


I cant see one on the head itself. The one on the manifold seems to be the one which needs a large Allen key , I will try that ( it needs to be freed at some time anyway). The one down on the block needs a smaller allen key and wont budge ( advice appreciated especially as the key hole is now rounded!)

I have tried the engine again and this time had the thermometer to measure at the various areas. The raw water coolant areas were fine showing just a very slight warming of the water. On the fresh water side the header, heat exchanger, manifold and block ( and the oil filter) all warmed up to 40 degrees C but the head got up to 90 degrees and the sensor was showing 100. The water ways around the head seemed clear when I worked on the head. Anything else I can do without taking the dam head off again !!?...…..Good practice I suppose!

 

[PCUK]

Presumably the raw water pump is pumping OK?

 

[pcatterall]

Presumably the raw water pump is pumping OK?

Thanks
Yes pumping fine and working in the sense that the raw water goes in at around 13 and is coming out at around 16.

 

[PCUK]

Have you sorted this?

 

[QBhoy]

Take the outlet off the internal cooling system pump and check for flow. Sounds very much like it’s airlicked.

 

[Balbas]

Thanks for that.View attachment 80309View attachment 80310


I cant see one on the head itself. The one on the manifold seems to be the one which needs a large Allen key , I will try that ( it needs to be freed at some time anyway). The one down on the block needs a smaller allen key and wont budge ( advice appreciated especially as the key hole is now rounded!)

Hammer the biggest torx socket in that you can and then get it out using an impact gun or an impact screwdriver (if access is good enough that is).

 

[pcatterall]

Thanks all. Not sorted the problem yet. I have been making my 'lashed up' raw water system more permenant ( it had been sucking out of a bucket which I kept having to fill!) so I have constant tap water supply and dont have to keep filling the bucket!.
I recognise that I need to get all the drains working so that I can 'service/winterise' the engine.
Now searching for an impact gun to add to my tool kit!.
The drain in the block will be replaced with a hex head bolt rather than an allen key type.

 

[ghostlymoron]

I've got some small Stillsons that are excellent for removing things like this if there's 3mm or more protruding. They grip tighter with more force unlike Moles.

 

[sutton sailor]

The thermostat should have it's opening temperature marked on the upper side of the flange, usually something like 88 deg C. If you doubt that the thermostat is opening correctly. Then you can test it by placing it in a saucepan of cold water on your cooker and slowly heat the water until the thermostat opens, note the temperature at that time. as the temperature drops the thermostat should close again. Just because it is new is no garantee that it will work ok. If you do not have a thermometer to read that temp then by checking that it has opened before the water boils will give an indication, as long as you do the test at sea level and not on the top of a mountain.

However The fact that the raw water never gets hot, is as it should be, assuming the raw water pump is working well, the function of the raw water initially is not to cool the fresh water which is already cold but to mix with the exhaust gas so as not to burn the rubber and plastic parts of the exhaust system. When you first start the engine from cold the thermostat should be closed and no water will flow through the engine apart from a tiny flow which passes through a small hole in the thermostat flange. the first thing to heat up will be the exhaust manifold. It is only when the water in the cylinder block jacket has reached 88 deg C or some such figure that the thermostat opens and some fresh water will now flow through the heat exchanger. Have you got one of those remote thermometers that work by reading radiated heat, they are very useful in these situations.
Best of luck.