Almonds
Active Member
- Posts
- 101
- Location
- Stoke-on-Trent / Nottingham
Having some overheating issues with the 300tdi on a recent ~200 mile run. Importantly, the fender has been stood in storage for around 8 months because I didn't have access to regularly drive (was overseas).
Symptoms:
1. Getting up to temp much quicker than usual, obvious from both the water temp guage and the warm air out the blowers.
2. After around 10-20 miles driving water temp guage goes into the red.
3. When stopped and playing with the fan's thermostat dial, it seems to indicate coolant temp around 90°C which seems a bit normal to me, the temp probe is in the rad top hose.
4. Expansion tank feels cold, thermostat housing and top hose hot too hot to touch for more than a few miliseconds (could just be my paper-thin skin though). Bottom of the radiator noticably cooler than the top.
5. After letting everything cool, started her up, looked into the expansion tank and blipped the throttle but coolant doesn't seem to be circulating.
6. I wouldn't say that there was a very evident sizzle or smell of oil when popping the bonnet after a several tens of miles, which is usally a bit of a giveaway.
7. Through the journey, the EGT peaked at about 450°C up a long hill. My experience is that it can stray a little higher, but I prefer to keep under 500. Normally, at 50mph in 4th or 5th it sits around 300-350°C, this was the same on this last run. Granted this is measuring exhaust gas temps, but it's an extra bit of info to help diagnose.
8. No evidence of coolant or oil leaks (yes, there is the right quantity of oil in it; checked and topped up lubricants before setting off).
I believe the readings on the water temp sensor and the in-cab guage.
The lack of circulation is bogglin' my noggin' and seems to be the real culprit. Feels like airlock, lack of pressure (headgasket?), or some kind of blockage/severe restriction.
Things I've checked/done:
1. Flushed system with Wynn's cleaner, replaced 5L coolant + 5/6L water (though how effective the flush would be if not circulating
)
2. Checked expansion tank cap, rad cap and stat cap seals - rad and tank fine, the stat o-ring was completly shot, like smushed into bits, I'm running with a brass cap rather than plastic if that makes any difference.
3. Water temp sender (replaced like-for-like with black insulator for Fender) - seems fine, all signs indicate it's the right one and working correctly **though this was bought from Amazon in anger as I was in urgent need**
4. Replaced thermostat with new (though checked the old one in a pan of water and it seems to working fine despite being a truly filty one).
5. Main earth - seems fine (RE water temp sender).
6. Removed all hoses - cleaned remnants of sludge, ditto for the radiator, which may be a tad blocked, maybe, maybe, maybe.
7. I noticed that the hose bleed pipe (PCH117840) was blocked, I couldn't blow through the stat end at all, the rad end worked fine.
8. Removed water pump - seems fine, very nearly torqued off one of the long bolts, but thank fran it held together for removal.
What I'm thinking:
a) The obvious one: head gasket / warped head - but I'm not seeing any oil in the coolant / coolant in the oil; zero signs of any landy-flavoured margarine, though this could just be because the coolant isn't circulating round? Additionally, I'm not losing any oil, nor am I loosing any coolant....exhaust smoke seems perfectly respectable also (not white, not black, and not bellowing out).
b) Could this all be as simple as an absolute monster of an air lock that won't go away, caused by the combination of the busted stat cap o-ring and the blocked hose bleed pipe? Perhaps I'm being thick.
If anyone has two cents to throw my way, I'd appreciate it.
In the meantime, I'm going to replace the blocked hose, stat cap o-ring and fit the water pump back once gasket arrives; re-fill/bleed and see if it's circulating... to be continued...
Cheers,
Alm
*EDIT* Just found this: https://www.landyzone.co.uk/land-rover/def-110-tdi-300-overheating.179767/
Sounds a little familar....
Symptoms:
1. Getting up to temp much quicker than usual, obvious from both the water temp guage and the warm air out the blowers.
2. After around 10-20 miles driving water temp guage goes into the red.
3. When stopped and playing with the fan's thermostat dial, it seems to indicate coolant temp around 90°C which seems a bit normal to me, the temp probe is in the rad top hose.
4. Expansion tank feels cold, thermostat housing and top hose hot too hot to touch for more than a few miliseconds (could just be my paper-thin skin though). Bottom of the radiator noticably cooler than the top.
5. After letting everything cool, started her up, looked into the expansion tank and blipped the throttle but coolant doesn't seem to be circulating.
6. I wouldn't say that there was a very evident sizzle or smell of oil when popping the bonnet after a several tens of miles, which is usally a bit of a giveaway.
7. Through the journey, the EGT peaked at about 450°C up a long hill. My experience is that it can stray a little higher, but I prefer to keep under 500. Normally, at 50mph in 4th or 5th it sits around 300-350°C, this was the same on this last run. Granted this is measuring exhaust gas temps, but it's an extra bit of info to help diagnose.
8. No evidence of coolant or oil leaks (yes, there is the right quantity of oil in it; checked and topped up lubricants before setting off).
I believe the readings on the water temp sensor and the in-cab guage.
The lack of circulation is bogglin' my noggin' and seems to be the real culprit. Feels like airlock, lack of pressure (headgasket?), or some kind of blockage/severe restriction.
Things I've checked/done:
1. Flushed system with Wynn's cleaner, replaced 5L coolant + 5/6L water (though how effective the flush would be if not circulating
)2. Checked expansion tank cap, rad cap and stat cap seals - rad and tank fine, the stat o-ring was completly shot, like smushed into bits, I'm running with a brass cap rather than plastic if that makes any difference.
3. Water temp sender (replaced like-for-like with black insulator for Fender) - seems fine, all signs indicate it's the right one and working correctly **though this was bought from Amazon in anger as I was in urgent need**
4. Replaced thermostat with new (though checked the old one in a pan of water and it seems to working fine despite being a truly filty one).
5. Main earth - seems fine (RE water temp sender).
6. Removed all hoses - cleaned remnants of sludge, ditto for the radiator, which may be a tad blocked, maybe, maybe, maybe.
7. I noticed that the hose bleed pipe (PCH117840) was blocked, I couldn't blow through the stat end at all, the rad end worked fine.
8. Removed water pump - seems fine, very nearly torqued off one of the long bolts, but thank fran it held together for removal.
What I'm thinking:
a) The obvious one: head gasket / warped head - but I'm not seeing any oil in the coolant / coolant in the oil; zero signs of any landy-flavoured margarine, though this could just be because the coolant isn't circulating round? Additionally, I'm not losing any oil, nor am I loosing any coolant....exhaust smoke seems perfectly respectable also (not white, not black, and not bellowing out).
b) Could this all be as simple as an absolute monster of an air lock that won't go away, caused by the combination of the busted stat cap o-ring and the blocked hose bleed pipe? Perhaps I'm being thick.
If anyone has two cents to throw my way, I'd appreciate it.
In the meantime, I'm going to replace the blocked hose, stat cap o-ring and fit the water pump back once gasket arrives; re-fill/bleed and see if it's circulating... to be continued...
Cheers,
Alm
*EDIT* Just found this: https://www.landyzone.co.uk/land-rover/def-110-tdi-300-overheating.179767/
Sounds a little familar....
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