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Over heating 2 1/4 diesel

J

Jeffcars

In Second Gear
My SWB 2 1/4 is over heating have removed the thermostat and she still get very hot .water pump was replace about six months as the bearings had failed. Any ideas to the problems ,thanks
 
Welcome back. Is this the new engine?
First thing to find out is if your temperature sensor is correct. Too hot may just be a failed voltage regulator. Is your fuel gauge behaving itself? They use the same voltage regulator, and this is known to fail after 20 years or so.
 
I suggest you make sure the radiator is working ok.
A good back flush with a hose may make a difference.
Also check that air is getting through the cooling fins of the matrix.
It could be blocked up with flying insects.
 
Would be good to flush out the heater as well as the radiator tbh. The heater also gets an airlock and needs taking a hose almost off while engine has just started running (so the water is cold). As a general rule the diesel doesn't overheat if your radiator is ok. If your coolant is muddy then it probably is blocked.

Someone on here found out that one of the shock rubber bushes makes a very convenient bung for a hose when flushing it. :cool:
 
Richie_asg1 said:
Would be good to flush out the heater as well as the radiator tbh. The heater also gets an airlock and needs taking a hose almost off while engine has just started running (so the water is cold). As a general rule the diesel doesn't overheat if your radiator is ok. If your coolant is muddy then it probably is blocked.

Someone on here found out that one of the shock rubber bushes makes a very convenient bung for a hose when flushing it. :cool:
Click to expand...


Hello
thanks for for that coolant not the cleanest so will flush out the rad and the tip about the shock bush as a bung great idea..
 
Sounds like you have a lot of sludge build up and a partly blocked radiator.
If it is this bad you can take it off (with the front panel complete is easier) and lay it down to flush it out from both ends, shake out deposits etc. You may want to run a cleaner through the system when it is back together again. 10% citric acid would work and is cheaper than rad-flush products. This will convert the red rust to a black form which is smaller - so should come free eventually. What you will see is clear water turn to a black ink as more rust is converted and removed. Just flush that out and you should be good to go.
 
Can you see moving water if you run the engine with the rad cap off? That'll give you confidence that the impeller is still on the pump and doing it's job.

If it "boils" very quickly from cold, this might be escaping exhaust gases from a head gasket leak.

Food for thought.
 
radiator cap is worth a look. i think the series 3 ones are just under 1 bar pressure, which raises the boiling point (with coolant mix) to 115-120C region. pressurisation also increases flow through the engine in deliberately narrowed passageways (even holes in the head gasket for example)

without the pressurisation, flow drops slightly, boiling point drops back to amospheric pressure, you get localised boiling forcing water up and out the path of least resistance.

head gasket good shout, although youd hope to see other symptoms like water consumption and fluids mixing in the weeks months before the boil overs were common
 
Am highly interested in this troubleshooting thing. I have no experience with any overheating problems though. I've done diesel system, electrical on the old 2a, without prior knowledge, except for the repair manual.
My question is mainly, what causes one to think in a certain direction. Sorry if this isn't what Jeff wants. But if the waterpump was replaced last year, that's the place I'm interested in. How did it look, was there any sludge, oil, why was it replaced in the first place? The cooling system wasn't working I guess, but what made you blame the pump for that?
Again, sorry to bother you hardware diehards, maybe there´s another forum for psychotic thinkers like me...
 
hugh2a said:
My question is mainly, what causes one to think in a certain direction.
Click to expand...
For me it is experience of similar or exactly the same issues myself and how I cured it. Sometimes you do go down the wrong path and your 3 day efforts have absolutely no effect. You then rule out that and go onto the next logical reason. If you do electronic repairs (as I have taught myself) then you will realise there is often a chain of events, and replacing something that was the ultimate failure mode (i.e. the fuse) may only be a symptom of another cause. So we look at the whole system and identify what would cause this failure mode, In this example loss of flow or loss of cooling effort would do it, but is flow bad because the pump is bad or because the passages are blocked? He stated the water was muddy so was more likely that there was significant rusty sludge in there blocking the system rather than the pump that is relatively new. In an electronic example it could be that a capacitor was the original culprit causing instability and causing a transistor to fail shorted blowing the fuse.
It could easily be that the pump originally failed because of corrosion in the system wore away the pump seal as it is quite abrasive, allowing water into the bearings and corrroded & wore them out too, so the original problem is corrosion and if not cured will cause this new pump to fail also.
 
Thanks Richie. Only now I realise, that even if it were possible to measure the temperature in some hoses, it wouldn't make a difference, for any blockage will stop the circulation and cause all parts to get the same temperature. Moreover, I guess that cooling problems are not very common, so it's not worth the effort to try and analyse.

Jeff, one thing that I can think of, does the heater circuit work? I guess it's powered by the same pump but follows a different path. Does it heat up?
 
If its blocked in the cylinder block it will get very hot in the dead leg where the water is getting stuck. This will boil quickly and blow the rest of the water out, and you can hear it boiling. The blockages can be corrosion/muck which will flush out with some acid central heating (powerflush) cleaner or they can be calcium furring up (like a kettle) which you have to dissolve with descaler (like citric acid). The descaler needs time to work. You can put central heating descaler in and leave it a few weeks. You can get phosphoric acid c/h cleaners from a plumbers merchant that dissolve rust but you must flush thoroughly after, I made an adapter for the garden hose so I could flush it for a decent time . I had a furred head on a alloy V8 Merc - descale or £1200 job, got a lot of very good advice from Fernox tech dept who advise Fernox for vintage Rolls Royces. Descaller/cleaner worked, the Merc engine had small waterways that were prone to scale forming due to low flow. The metals in a c/h sytem are the same - iron, copper, ali.
 
Hello

thanks for all the help, I removed cleaned and flushed the rad only dirty water came out no big stuff,I also removed the water pump and that was still like new. The block and heater was also flushed out dirty but not that bad.i also removed the head and had that checked nothing wrong there, but I did find two tappet slides broken thou this would not cause the over heating. Well I've done nearly six hundred miles now and everything seems ok the engine does sound quieter and pulls better so I am thinking that there was something amiss with the head gasket.
 
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