P38A 2.5 diesel temperature problems

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tarphenry

tarphenry

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bury lancs
Hi all still having temperature problems but this morning after a short run, I checked the rad temp, and it was nearly cold at the bottom but hot at the top. I think its a thermostat that is not opening,is that correct?
 
tarphenry said:
Hi all still having temperature problems but this morning after a short run, I checked the rad temp, and it was nearly cold at the bottom but hot at the top. I think its a thermostat that is not opening,is that correct?
Click to expand...

You without question have a rad without the cross flow baffle. Looking from front of car, hot coolant should enter rad at right side flow DOWN to bottom then UP left side. No baffle means it flows across the top which will give you what you have.
 
the rad is 12 months old and has worked fine up until I had a slight water leak 6 weeks ago. when I bought it, i did the marble test and the marble did not roll across the top.
 
tarphenry said:
the rad is 12 months old and has worked fine up until I had a slight water leak 6 weeks ago. when I bought it, i did the marble test and the marble did not roll across the top.
Click to expand...

Then the baffle has failed. What you have is classic of no baffle. OR?
There always will be a little leakage across the top, i suppose if stat has failed shut you may get what you have. But on a decent run you will get an overheat. Check the stat.
 
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new water pump and thermostat arrived, no bleed hole, sent it back and a different one arrived no bleed hole is that correct. Havent tested rad yet, no marbles
 
tarphenry said:
new water pump and thermostat arrived, no bleed hole, sent it back and a different one arrived no bleed hole is that correct. Havent tested rad yet, no marbles
Click to expand...
not an OEM item then, you can drill a 6mm hole and fit the thermostat with the hole in the 12 o clock position. Test the thermostat in a pan of water, bring to the boil and make sure it opens.
 
The valve is only to stop air getting trapped, as I understand it. 12oclock. I drilled hole and works fine, there was little ball valve on the original. Old one jams on testing, new one didn't open until I pulled it open once by hand. Boiled fine then
image.jpg

image.jpg
 
Still having troubles with temp since overheat. new pump, new stat (tested) Checked the rad and the baffle is in(I can feel a great temp difference across the two hoses..Refilled and runs up to temp and sits bang on. however if i stop at lights the temp drops to halfway between 12 oclock and the line on the left of the gauge.It is also losing water I think ,but I cannot find any leaks ,carpets all dry etc. Is it possible that the head is cracked and I am losing water to the inlet,(i have occasional very poor tickover,which clears if I rev it)
 
tarphenry said:
Still having troubles with temp since overheat. new pump, new stat (tested) Checked the rad and the baffle is in(I can feel a great temp difference across the two hoses..Refilled and runs up to temp and sits bang on. however if i stop at lights the temp drops to halfway between 12 oclock and the line on the left of the gauge.It is also losing water I think ,but I cannot find any leaks ,carpets all dry etc. Is it possible that the head is cracked and I am losing water to the inlet,(i have occasional very poor tickover,which clears if I rev it)
Click to expand...
You sure the viscous fan is OK? If you had not changed he stat I would say the stat is stuck. Small water leaks can be a real begger to pin down.
A cracked head usually shows up on load, not when idling. I have one that would idle all day with no sign of an overheat, drive it up the hill from my place and it would boil in an instant. The exhaust pipe was full of coolant when I dropped it. My understanding is that heads usually crack around the exhaust where it's hottest but you never know.
 
your gauge pulls to the left (cold) when stopped?
And you said you recently renewed your sensors?

When you are looking at rad under bonnet, warm water will come in right hand pipe, circulate down around rad, then out the left hand pipe ONCE the stat has opened.

Left pipe stays cold suggests stat is stuck or there is blockage?

Personally I'd pull rad out, flush with hose pipe to see it flowing and then fill, plug and leave to see if leaking just to eliminate as they can fill up with muck.

Could warm it up without stat in see if makes difference to eliminate that

Did your old pump crumble to bits and is belt tight and turning it effectively?

Have you thought you may be losing water through heater matrix part of system?
 
Found the leak this morning,its only tiny on the pipe from the header tank.temperature is different on the two rubber pipes ,left is cooler than right. Stat was tested and opens correctly. old pump is in good condition, only changed because i had a spare one. Rad does not leak tested when I changed pump
 
tarphenry said:
Found the leak this morning,its only tiny on the pipe from the header tank.temperature is different on the two rubber pipes ,left is cooler than right. Stat was tested and opens correctly. old pump is in good condition, only changed because i had a spare one. Rad does not leak tested when I changed pump
Click to expand...

You would have a problem if left pipe was not cooler than right. Right is the hot inlet left is the cooled outlet. From a cold start after a couple of minutes you should be able to stop and hold the viscous fan with your hand. The temp gauge should never drop more than slightly below the centre position in normal driving..
 
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It always has been,just since the overheat that it is dropping.I am now wondering if it could be the gauge as it doesnt go past 12 oclock
 
Yes, thats what I meant. its the one thats unobtainable the two pin at the front of the head. I changed the ecu one /
 
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