Likes to over heat once and a while??????

[300TDi Disco]

Hi, Just after some info. I have noticed over the last week that the temp goes right up just below red. I opened the bonnet to find the water pipe to the thermostat is really stiff to squeeze (No dirty remarks please). I Have changed the thermostat about 2 months ago as well as a water pump & flushed the radiator out. It has been running better than ever until now. Would it be possibly be the head gasket?? What are the signs? Your help would be appreciated.

Regards

Matt.

[Range Rover Blues]

No it's the weather.

Kep a close eye on the water level, daily, whether it overheats or not.  If you are loosing a slow, steady amount daily then it can be a number of leaks (inclus=ding internal to the engine).

If it doesn't looseany water until it overheats then a head gasket is less likley.

Flushing a LR rad is usually not that succesful and I suspect you are a victim of sludgy radiator syndrome.  Only relaly diagnosed with either an infra-red thermometer or a new rad.  They cost about the same.

Check your fan is ok and locking up as the engine overheats, check for mud in front of the rad etc etc.


Look for the simple stuff before panicing about the engine.

[squaddie_fox]

you can do a sniff test on the header tank, if you can smell exhaust fumes i would suggest that the head gasket is on its way out.
is there any water in the oil or vice versa? another sign of the head gasket failing.

just replaced the head gaskets on a mates 3.9 disco. on an L plate and they were still the factory gaskets from new so i would be looking elsewhere for a leak of some sort.

the favourite is the pipes underneath the plenum chamber getting a pinprick hole in them or not being done up tight enough.

also, do you have the standard vicious fan fitted? if so, i would suggest changing it to an electric one. easily picked up from the local scrapper for a couple of quid. wire through a relay into a switch or an ignition live and away you go. helps with fuel economy a bit too.

but, saying all that, a pressurised system is usually down to an air lock somewhere in the system...

[Range Rover Blues]

Careful there, I rand Kenlowe for technical advice and they told me NOT to fit electric fans as they only shift half as much air as a viscous fan.

I'm yet to be convinced the electric fan on our TDi has made any difference at all.

[SteveGoodz]

Hi Matt,

I've just got over a problem with similar symptoms to yours ... only overheating now and then ... rad top hose rigid/uncompressable ... blowing coolant out from under the expansion bottle cap.

Replaced the thermostat - no difference  :doh:
Replaced the viscous fan coupling - no difference  :doh: :doh:
Flushed the radiator - no difference  :doh: :doh: :doh:
Replaced the radiator - problem cured  :dance:

[squaddie_fox]

Careful there, I rand Kenlowe for technical advice and they told me NOT to fit electric fans as they only shift half as much air as a viscous fan.

I'm yet to be convinced the electric fan on our TDi has made any difference at all.

thats why i didn't say the kenlowe fans, they are over priced and i seem to remember them quoting some silly figures in their ads. twin fans or two individual fans works well.

i had leccy fans on my VM, they are prone to overheating at the slightest opportunity. with the electric fans i managaed to overheat it once, whilst pulling a disco uphill in blistering heat. all the coo.lant ran to the back of the header tank as the pipes are at the front it stopped the flow.

[Range Rover Blues]

If a viscous fan consumes 2 hp at "idle" and up to 4hp at full blow, that's the equivelent to 3,000watts, so assuming the electric fan is 100% efficient, 250amps.

I doubt you will find any fan,or combination thereof that will output anywhere near the same as a Viscous fan, in truth the 13" HD Kenlowes are quoted at slightly more than half the air flow in CFM, Pacet are little better and make more noise (less efficient).

You can argue that the cooling system when in good nick is over-engineered for the UK market, but by removinng the viscous fan you eat into that safety margin considerably.

I'm not syaing don't fit electric, I have them on Blue, I'm saying think carefully.  I tow regularly with the LSE, it's auto and has airconn all of which make things worse for the cooling system.


BTW, the fans on Blue will melt a 30amp relay if they are on a lot, which they are when I'm laning in the summer.

[squaddie_fox]

the fans on mine were switched through a thermostat that didnt work properly so they were wired through to the battery on separate circuits, one for each, and switched via a 30 amp fuse... :roll:

[fordlltwm]

If a viscous fan consumes 2 hp at "idle" and up to 4hp at full blow, that's the equivelent to 3,000watts, so assuming the electric fan is 100% efficient, 250amps.

I doubt you will find any fan,or combination thereof that will output anywhere near the same as a Viscous fan, in truth the 13" HD Kenlowes are quoted at slightly more than half the air flow in CFM, Pacet are little better and make more noise (less efficient).

You can argue that the cooling system when in good nick is over-engineered for the UK market, but by removinng the viscous fan you eat into that safety margin considerably.

I'm not syaing don't fit electric, I have them on Blue, I'm saying think carefully.  I tow regularly with the LSE, it's auto and has airconn all of which make things worse for the cooling system.


BTW, the fans on Blue will melt a 30amp relay if they are on a lot, which they are when I'm laning in the summer.

I was pulling relays out in a scrapyard and found that a ford granada estate has a 70 Amp relay for the fans, it's about 2 inches high

[Bowie]

I fitted a twin setup from a Mondeo 24V with air con, the cowling is almost a *PERFECT* fit to the Range V8 radiator, actually clipping in place along the upper and lower edge with all but the tiniest amount of trimming required. I added a small bracket just to hold the top left (as you look at it) corner of the cowl off the fins and job done.

2 30A relays running straight from the battery and they are temperature controlled via MegaSquirt, 85C on, 83C off.

Works very well even when crawling or towing -anything above 45MPH and they don't come on at all :)