Morning Hive mechanical mind
Brought the truck back from wales to suffolk a while back. About hour 4 into the journey, the temp gauge climbed from its usual half way point up to 3/4 then when I took foot off loud pedal, it dropped back to normal.
Did this 4/5 times, mostly when engine under increased load.
Checked coolant reservoir and it was very low.
No obvious leaks so topped up and kept eye on it.
Engine was a full rebuild about 4k, inc new OEM head gasket seal. No signs of oil in coolant or foam in oil.
Rad is new and appears fully functional, fan operates well.

I have removed and blanked egr and cooler, removing and bypassing the cooler.
Looking at the back of the block, under where the cooler bypass hose runs, there is a recent wet patch of what i think might be coolant!
Does anyone have a photo of the back of the block that shows the route of the metal pipe the cooler bypass hose goes? Am worried that i might have dislodged this and its now the culprit for my diminishing coolant levels!
Thanks in advance guys!!

Hi Jim

Where is the wet patch exactly? reason I ask , is when mine was first done by a garage , I had water dripping down the back of the block onto the bell housing...unfortuantely it was a strip of the HG to repair ..( garage just put radweld in it , which you can imagine I wasn't overly impressed with! ) but saying that it may be the pipe but I have my suspicions ...sorry...

Hi ronnie, pretty much as you describe as far as I can tell! I can see if on top of the bell housing. Its a pig to see into the area, Im going to take it too work tomorrow and stick an inspection camera into the back of it so I can get a proper look! Really hope its a leaking pipe!!! 😒

This might be of help to you

http://www.mercedes.gen.in/WP35/other-st...itsubishi-l200/

Yeh fielder had that pipe go on him resulted in the aa being called

@tmw4562 - spot on, thanks for that article! having managed to wedge an inspection camera down the incredibly small space available I discovered the hose in question with the consistency of swiss cheese! Tried to take a picture with no success! If I can, Ill try and do a pictorial "how to" when I get into this and sort it - thinking about trying to replace it with a custom bent metal pipe instead of a rubber one to stop the next one melting.

It does get quite hot around the back there a 3 ply silicon hose might do better and wrap it in heat tape