td5 discovery overheating?

Re: Discovery Td5 temp hi all,
i will bump this post as it seems exactly like mine, i can be motering quite happily at 70 on the motor way, i noticed it first while in cruise, that the temp was in the middle quite normal, and all of a sudden it seemed like the cruise shut down and refused me to much throttle, i looked at the temp and it was just below the red, i eased off to about 50, and the temp came down back to normal, after a few more miles i stopped at a garage but everything looked good, so i got back under way, 10/15 min later overheat again, so i just kept between 50 /60 to finish my trip, this kept the temp at normal, about another half hour.

i am going to be looking under the bonnet tommorrow, but wondered, would a weak antifreeze mix have anything to do with it.

i did wonder about the belt, but that would show on the ignition light, next thought was the viscous fan, or even, and i was not even aware that i had one, an electric fan, this started working, which surprised me, i had to check.

as far as i know a temp sensor would work or not, not work intermittently

any ideas
voith

Just some suggestions -

The thermostat might be sticking in the closed position or not opening properly.

Faulty viscous fan

Faulty water pump.

you need to find out if it is really overheating or not. as soon as it does it next time, jump out and check the hoses. if its extremely hot then susupect the stat or the rad/water pump.
(try a new fan belt. it could be slipping just at high speed).

if not really overheating, then suspect a faulty sensor somewhere.

hi,
thanks for your replies, well i have not been able to check much due to work, however following my last trip as reported above, i have only just today been able to check it out, (i have not used it since then) i had to top up the rad, so due to the time of year, i put in 1 litre of antifreeze, and about the same or a bit less of water.

i checked the serpentine belt, (it was new approx 2000 miles ago) all seems ok there, the water pump appears ok no movement on the shaft, no leak marks from the seal, i checked the rads for external blockages and all three seem clean.
after filling up i run it to temperature, and checked all visible pipes for leaks, and looked under, with the engine running for apparent leaks, still no joy.

i have used one bottle of k-seal, in case the heater matrix was leaking, as i have mentioned in another post.

i have now found out that it is the function that if it goes into the red that the engine will reduce, and also shut off aircon (if running) to reduce the load.

what slightly worries me, is if its not external, then it has to be internal, i have not seen a td5 head gasket, so do not know if the waterways can leak toward the bores, to get a clue by any hydroulic locking, which i am not getting, also i am not showing water in the engine oil.

in my old disco 1, the gasket leaked outwards, but in this case i can see nothing.

can the workshop interrogate the electrics, to read a log, as in a computer of faults?
as in if it is plugged in, and after interogation, it says oh yes on the 6th of so an so, there was a temp fault in the whatever???

just a thought
thanks for reading
voith

you can usually tell a HG problem via water in the oil and vice versa.
i hope its not that!

maybe summat as simple as an air lock?
try running the engine for a while (till hot) with no cap on, then replace the cap whilst still running.

the stat could be sticking? are they easy to replace on the td5?

you what to give it a good flush out to get rid of that k seal crap before you bung everything up

hi all,
thanks for the replies, sorry this thread is over a long period, but as i do not do much driving.
well out today, again, and i can eliminate bad sensers, as it over heated after about 10min of 70 mph with the temp gauge in the middle of the range,then it rose sharply to just below the red and cut the CC off, i was able to stop almost immediately and opened the bonnet to see that the header tank was spitting, after about 5 min of engine running at tick over and the electric fan working, it was back down to its normal position, got under way and it kept at that level, all the while i ran below 50MPH.

the consistent thing is that it overheats when its working ie going up hill,

@slob, have you a specific reason why you do not like k-seal, or are you against all radseal type products?? the only reason i used this, (and i would have used radseal if i had not seen k-seal mentioned here) was that i had a minor water leak, but could not determine where it was, so guessed the possibilty of the heater matrix, so as it was a minor leak,thought i would try this instead of the expence of a new matrix.
thanks for all answers
voith

by nature them tings block water ways. and the last thing you want to do is bloke waterways.... it might save you the cost of a heater core just now... i know of a fews peeps that have used them things and ****ed the injun right up. of course sometimes its ok but why take the chance?

I wonder if your thermostat is not opening fully - perhaps just enough to allow some water out for cooling under normal load but not enough to cope with increased load.

Test it by removing and putting it into a pan of water on the cooker - insert a thermometer and heat the water - watch to see at what temp the stat opens and that it opens fully.

hi all,
just an update on this problem, i finally put it in the shop, as i do not have time to sort it out, i had a good set of parameters for them to work with, i could run around at up to about 50 with no problem all day, but if i did a run to a certain place, about 20 miles away, at a a point it would start t overheat, and this was replicable.
they first did the combustion check, no go, pressure check, no go, thermostat checked, this was only opening halfway, changed that, no change to problem, checked the water pump, this had a small leak showing so i got them to change that, but still no improvement so decided to check the gasket anyway, so we are now at this stage, waiting for parts, i have inspected the head,gasket,and block, but we all can not find any conclusive fault, but what was noticeable, was that one piston, apart from the star shaped mark, which we associate with the injector spray pattern, this one piston was white stained.

this we assume to be (hopefully) to be a water mark,ie steam where its been heated, so there you go, an update
voith

hi sounds like your radiator is blocked,when under load it over heats and if you back off power temp returns to norm, good luck mark

Yeh but!

Did you check the radiator out and flush all that K-seal crap out?

Is the head being pressure tested ?

hi,
yup, rad was flushed first job, flow tested, and checked while running with a meter to check the temp gradient. and the head will be pressure tested.

another symptom, was when they checked on the run, they had the heater running, which was working well up to the replicable known trouble area, which i might add is on the flat and had been for best part of 5 miles, the heater goes cold, and a min later the temp goes to the red, ease off, a few min later the heater comes back, and the temp goes down.

anyway i am hoping the bits will come soon and it will be fixed
voith