300TDi - Pressurizing cooling system

Im having a few issues with my engine after this weekend. The weekend started with my stat sticking and me overheating on the side of the M25. After getting to a service station (luckily 1/2 mile up from where I stopped) and cutting out the stat it all seemed OK, well until I knackered a pipe by catching it and it wore on a pulley, I had a spare tho so changed that and refilled the system again. Over the weekend I had a fair few overheats, mainly due to mud clogging up my rad. It seemed to be OK though, power was still there and cleaning the rad a few times each day (before it hit the red again) seemed to keep it under control. On the way home it lost a bit of power and heated up again, after alot of rinsing out I managed to get it driving, as long as I kept it off boost it stayed cool but if you went over 2500rpm it would get hot again.

Anyway, got it home and took it to work today, the cooling system was down and it needed bleeding again, I done that and drove it home to do a new water pump, stat and rad on the drive. On the way home it struggled really bad, wouldn't rev over 3000rpm and was gutless. I got home and it had pressurized the cooling system, the bottle was at the top yet the pipes and stat housing were empty so I assumed head gasket. I have taken the head off and the gasket rings are all OK although the gasket itself was stuck a bit to both the head and block so was a bit of a mess. I dont think the gasket was blowing but was wondering if these head are prone to either warping or cracking? Im going to send it off to an engineering place to be tested but thought I would ask on here for any known issues?

So, what yah know?

Iv just had mine re built and the guy at the engineering shop said that they are prone to warping if they have been over heated. But a straight edge test and pressure test will tell you what you need to know.

Jongould said:

Anyway, got it home and took it to work today, the cooling system was down and it needed bleeding again, I done that and drove it home to do a new water pump, stat and rad on the drive. On the way home it struggled really bad, wouldn't rev over 3000rpm and was gutless. I got home and it had pressurized the cooling system, the bottle was at the top yet the pipes and stat housing were empty so I assumed head gasket.

So, what yah know?

Click to expand...

I know that if I had a problem with an overheating TDi 300 it wouldn't be running at 3000rpm !!

Was the coolant in the header tank hot?

My wife's Def 110 was overheating quite badly and I tried just about everything bar headgasket. I changed the sta, the water pump no joy I then flushed out the rad and cleaned the outside - no joy.

So I replaced the rad with a new one and she wasn't overheating so much but the header tank coolant stayed cold.

I then replaced the 2 into one hose with the one-way valve and now she runs perfect.

In my case I'm sure it was a combo of rad blocked and this one-way valve pipe that was causing my problem.

thebiglad said:

I know that if I had a problem with an overheating TDi 300 it wouldn't be running at 3000rpm !!

Was the coolant in the header tank hot?

My wife's Def 110 was overheating quite badly and I tried just about everything bar headgasket. I changed the sta, the water pump no joy I then flushed out the rad and cleaned the outside - no joy.

So I replaced the rad with a new one and she wasn't overheating so much but the header tank coolant stayed cold.

I then replaced the 2 into one hose with the one-way valve and now she runs perfect.

In my case I'm sure it was a combo of rad blocked and this one-way valve pipe that was causing my problem.

Click to expand...

I didnt know it wouldnt rev till I was driving home so had no choice. It still had flow, all pipes and the rad were getting hot and it wasn't running a stat, it all seemed OK in the garage, bled up and held temp, it didnt overheat on the final journey but just had no power, when I got home the system had pressurized and there was lots of air in the system, this is whats making me think head has warped, it went of for testing today so will wait and see, if it wasn't the head then oh well, I needed a few helicoils fitting anyway so not a wasted job. When it goes back its having new rad, pump, pipes e.t.c.

I keep saying to myself that the amount of money I spent on the def is money well spent as we plan to keep her 'forever'

She should run lovely and cool for another 10 yrs now.