Thread: Temp Gauge Rise

Leaked hot coolant smells pretty bad. Have you checked your coolant level since the trip? Could be a weak head gasket pushing coolant out of the reservoir cap. Or even a split hose or leaking radiator.

Hi Fausto79,

It is normal for the engine to get warmer on climbs when you are loaded but it shouldn't get too hot. I had the same thing happen on my 300 Tdi, but unfortunately for me, the smell was due to cooking the head. Thank you Lucas electrics and your wonderful non-functioning temp gauge! The original gauge SUPPOSEDLY registers when it hits around 105 degrees so is not much chop. I smelled my car overheating before the gauge even registered and pulled over just in time to stuff the head and for the No. 4 piston to leave some lovely scrapes on the cylinder wall. You might be lucky and the smell is something else. Check for any leaks for clues.

When I had the engine rebuilt (thermostat, radiator & hoses replaced, head re-done, etc) I finally got around to installing my VDO temp gauge. Better late than never I guess! Although it seemed ok at the time of the rebuild, it turns out the thermo fan was on the way out as well. It only showed itself when pushing through the hills near Bridgetown on a 40+ degree day while fairly loaded. The new VDO gauge registered the engine staying hot (~ 110 degrees) but the needle on the dash had barely moved. I backed way off on the hills and let the temp go down.

You may have a number of cumulative issues with your cooling system like I did (original radiator and a dodgy thermo fan) so it may take some trial and error to diagnose yours properly. With a 300 Tdi your cooling system needs to be well maintained, so once sorted, you would be wise to invest in a proper temp gauge and probably a low coolant alarm also (next on my long list of jobs).

They are a pretty tough little engine and it takes a bit to properly nuke them. Go through the usual list of suspects (as you are doing) and hopefully you haven't done any permanent damage. Good luck it.


Cheers,

Cripesamighty

Originally Posted by bee utey

Leaked hot coolant smells pretty bad. Have you checked your coolant level since the trip? Could be a weak head gasket pushing coolant out of the reservoir cap. Or even a split hose or leaking radiator.

no its not a radiator water type smell. the coolant level is still good. the smell is more like burning chemicals, kinda like burnt clutch or brakes. it was revving pretty high when i was getting out of the soft sand. it almost had another tinge to it though, like it was clutch fluid burning or PS fluid burning. hard to explain. but definately more like a clutch smell rather than a coolant smell.

i want to go again somewhere soon but im scared there is an underlying issue.

Do you have an aftermarket temp gauge fitted? Because what I have heard and experienced the factory fitted gauge is allergic to movement from its "comfort zone" until the whole cooling system is ready to pop.
I have fitted low coolant alarms and capillary type gauges to both our Tdi's and they will fluctuate up and down in the normal course of driving, as a matter of fact just as you described, when travelling at highway speed the temp climbs then moves up more on fast hills dropping again on the other side of the hill, dropping to a lower level when driving around town.
So if, as has been said, you are loosing coolant, that is cause for alarm, if not it may be the symptom of what I suspect of our own Disco's, a 16 year old radiator that may be less than perfect, but fluctuations of a small scale I would call normal for an older vehicle. Gaz

Originally Posted by gazby

Do you have an aftermarket temp gauge fitted? Because what I have heard and experienced the factory fitted gauge is allergic to movement from its "comfort zone" until the whole cooling system is ready to pop.
I have fitted low coolant alarms and capillary type gauges to both our Tdi's and they will fluctuate up and down in the normal course of driving, as a matter of fact just as you described, when travelling at highway speed the temp climbs then moves up more on fast hills dropping again on the other side of the hill, dropping to a lower level when driving around town.
So if, as has been said, you are loosing coolant, that is cause for alarm, if not it may be the symptom of what I suspect of our own Disco's, a 16 year old radiator that may be less than perfect, but fluctuations of a small scale I would call normal for an older vehicle. Gaz

Thanks Gaz,
No i do not have aftermarket gauge. It is factory, so i was a bit scared, but it went down as quick as it went up. Coolant level is still the same. Which is why i am hoping it is a cooling system issue rather than a head gasket issue. Still, for it to move like that probably means i got the poor girl pretty hot.

Does the clutch fan make noise? I have the V8 petrol and put a new viscous coupling on the fan and when the engine is hot you can hear the fan running (sounds like a jet engine is under the bonnet) and feel the power drain on the engine.


Clutch fans usually move a lot of air and make noise when cold (first start of day) as the viscous oil/fluid circulates inside the chambers and then slows off (clutch mode) until warm/hot air from the radiator is drawn over it effectively causing the fan to be locked to the water pump and not freewheel anymore. Usually can be heard by air movement noise (the jet engine).


Some people prefer thermofans (electric) but I do like the simplicity of the viscous coupling clutch fan and they are effective. Clutch fans sometimes leak the viscous fluid out, so check for oil/fluid leakage.

I had similar issues with my 300tdi manual. I eventually replaced the radiator, viscous fan and thermostat (plus all hoses). As my tdi didn't have a full service history I thought it was worth the money to know that the whole cooling system had been sorted. The 1st thing I would do is install an Engine Watchdog (I use a TM1) and a low coolant alarm, at least then you can get a more accurate reading on your temp.

My TDI had similar problems so I removed the fan clutch and found it was leaking fluid. Money was very tight at the time so instead of buying a Chinese clutch I drilled and taped a hole in the front of the clutch and fitted a 45* grease nipple. Gave it a few pumps of wheel bearing grease and problem solved. This is a temporary fix and was only used until I could afford a good quality replacement.
Got me out of trouble but do at your own risk as too much grease and your fan might fly to bits.

Dave