Topic: rapid overheating (Read 7975 times)

jkseries · « **on:** December 16, 2009, 08:03:42 »

Could someone please help me sort this one out. Driving home form work last night (20 min run) all was fine until about 2 mins from home my temperature needle SHOT up.

This has happened before but last time it was low on coolant.

I'm almost certain it was fine last time as I'd checked everything at the end of last week.

So something is wrong.

After topping it up last night I looked for leaks and there don't seem to be any.

I've got no pressure in the expansion bottle which indicates the head is OK so could it be the water pump.What else could it be?

Any advice would be be greatly appreciated.

Thanks

J

crazymac · « **Reply #1 on:** December 16, 2009, 09:24:10 »

If it was low on coolant last time? And you had to top up the coolant this time? Then you are loosing water somewhere!!

Is the viscous unit still working? Get it up to temp then turn the engine off and try to turn the fan, it should be difficult to turn.

You can also check to see if the water pump is working, Take the filler cap off from the top of the radiator and start the engine, as it comes up to temp you should see a visible movement of water in the rad. This will also help to remove any airlock from the last fill up which you may have missed?

jkseries · « **Reply #2 on:** December 16, 2009, 09:43:32 »

Ok thanks.

I thought I did quite a good job of getting rid of air locks but I might have missed something.

On with the spannering

wizard · « **Reply #3 on:** December 16, 2009, 20:17:20 »

What you driving fella

200 Tdi
300Tdi
Td5 or v8

wizard

jkseries · « **Reply #4 on:** December 17, 2009, 18:00:07 »

Sorry it's a 300TDI.

I ran it for a while yesterday and then bled the system and there didn't seem to be excessive air. Not that I could tell with an even so quiet engine running right in front of me.

bogie · « **Reply #5 on:** December 17, 2009, 20:41:04 »

Could be a duff thermostat,stuck shut or half open?????????????????

burgerman · « **Reply #6 on:** December 18, 2009, 09:00:18 »

"topped it up and checked for leaks" seeems to contradict its self, Ie - if no leaks there would be no need to top it up ?? Im not being cocky with this comment :) I would pressure testing the water system if you are able to, or get a local garage to do it for you ?? good luck

bogie · « **Reply #7 on:** December 18, 2009, 15:47:09 »

Get it sniffed,costs a fiver!

Range Rover Blues · « **Reply #8 on:** December 18, 2009, 20:12:48 »

300 TDi has the water pump quite high up in the water jacket, so if it looses some water it will overheat. It must be leaking somewhere. Ours went on the heater pipe behind the head, it was chaffing.

jkseries · « **Reply #9 on:** December 18, 2009, 22:59:53 »

I've got lots of things to check.

After today I'm wondering about the thermostat.

On one of my trips today the temperature was fine. On another the needle moved quite high then back down then up again.

Interesting stuff

Range Rover Blues · « **Reply #10 on:** December 18, 2009, 23:08:54 »

Going high then coing down sounds like a circulation problem so check the 'stat. IIRC the stat is a 2 stage one that is double-ended, check both ends are as they should be and don't fit a cheap one as I've found they don't fit very well.

jkseries · « **Reply #11 on:** December 19, 2009, 10:00:35 »

Sounds like a plan. I think i'll drain and flush the system at the same time.

Rossko · « **Reply #12 on:** December 19, 2009, 11:06:42 »

Weak antifreeze?? As you bowl along the water in the rad gets cooled nicely and WILL turn to slush in the absence of enough antifreeze. Then the water doesn't circulate and the engine overheats rapidly.

lurch_917 · « **Reply #13 on:** December 19, 2009, 14:48:47 »

depending on what temp youve got out side id go with week anti freeze mix rad gets slugie then

jkseries · « **Reply #14 on:** December 20, 2009, 18:05:18 »

To add another thing into the mix. Went out for a run today. Got up to temperature nicely and then sat.

Brilliant i though. got home to find the expansion bottle bubbling away nicely with the needle still reading normal.

A new thermostat and flush it is then.

RRB you said don't fit a cheap stat. I've looked at the usual places and they only seem to be about £5. Where would an expensive one come from? LR?

Thanks J

Range Rover Blues · « **Reply #15 on:** December 21, 2009, 00:42:36 »

From memory I'd say that the cheap ones have a flat plate on the bottom ned, the end you don't see on a "normal" stat, this closes off the bypass flow once the engine heats up. Better ones have a dished plate which is then sprung.

Go for branded, or OEM. If in doubt I've found Devon 4x4 very helpful with obscure stuff, and if you have deep pockets Rimmers are just as good.

jkseries · « **Reply #16 on:** December 21, 2009, 12:35:34 »

Brilliant.

Thanks

J

BigA · « **Reply #17 on:** December 21, 2009, 14:22:24 »

Going on from what Range Rover Blues has stated, I replaced a thermostat a couple of years ago with one from Halfrauds, had no end of trouble after it was replaced. I replaced it again with an OEM and sorted it out nicely.

jkseries · « **Reply #18 on:** January 10, 2010, 16:26:41 »

Right... this is till ongoing. It now has a new stat and water pump but it's still trying to over heat.

I've just been reading about 'p' gasket problems. It sounds like mine is leaking from a similar place. Is it common for the 'p' gaskets to go?

I'm struggling to find why mine is over heating. The heater NEVER gets hot so could be a blockage their but surely the rad in the heater isn't crucial to the cooling of the car.

After a run out today (needle sat at about 3/4 ) I could hear a hissing from behind the water pump. I felt the radiator. The top was consistently HOT across the width and the bottom was consistently cool.

I would have expected it not to be even if it was blocked.

Where can i look next? Investigate the 'p' gasket?

Can someone tell me how the water flows around the engine. Hot water into top of rad. water falls through rad and is cooled. Water pump pulls water from bottom of rad then back into engine? Something like that.

Thanks

J

BigA · « **Reply #19 on:** January 10, 2010, 19:11:12 »

recent issue i had with over heating was with the very small breather hose going from the stat housing back to the header tank being blocked solid. this was causing air locks in the stat housing and preventing water from circulating? only found it when i was so [!Expletive Deleted!] off with it all that i had all hoses off whilst flushing the rad.

jkseries · « **Reply #20 on:** January 10, 2010, 19:19:12 »

Thanks for that.

Did you have the same problem with your heater?

There are all these symptoms and I just can't tell what they're pointing me towards.

I guess it's going to need all stripping out and flushing through. I'm a little concerned about this hissing now though.

J

crazymac · « **Reply #21 on:** January 10, 2010, 20:59:08 »

Your rad should be an even temp all over, if it is cooler at the bottom then that suggests a blockage or an airlock.

If your P gasket was leaking then you would see a little tell tale of a mark below where the water is running down the block, usually this is the bottom behind the pulley.

When you refilled it, did you take the top bung on the rad out and fill there 1st then fill through the expansion tank? Once you have done that then run the engine with the bung out and you should see the water moving through.

Also the small rad in the heater is integral to the system, the water flowing through there is what provides the heat! Again because you aren't getting heat inside suggests an airlock or blockage.

Have you tried to flush water through the system? Take the top hose off and stick the hose in the rad, then with the expansion tank cap off see if the water is being forced through.

jkseries · « **Reply #22 on:** January 10, 2010, 21:43:51 »

I have flushed the system. Before I did anything else it seemed like the easiest thing to do.

Yep topped up the rad. Then expansion the thermostat housing. Just been back out to it to top it up ready for the morning so gave the heater hoses a squeeze while i was there.

I know that the little rad is integral to the heating but wanted to know if it was integral also to cooling.

If the rad isn't a constant temperature could it be blocked?

Also from an earlier post i checked the thin hose from the top of the thermostat housing to the bottom of the expansion bottle. It is clear.

Thanks for all the help.

J

Disco_Dennis · « **Reply #23 on:** January 11, 2010, 14:17:29 »

I had these exact same symptoms recently on a friends 300tdi, :roll:

We changed pump, hoses, gaskets and it turned out to be a blocked rad - even flushing/blowing it through didn't clear it :roll:

You need to drain the rad, and take it out - if it's really heavy replace it, if not try flushing or blowing it out with a air line (not too much pressure, though!) :shock:

Changed the rad and all was perfect.

I would get the gas sniffer on it, too it might already have done the gasket - although I hope not [-o<

If you don't sort it out, it WILL blow the head gasket on the 300. I've seen it soooo many times now. Cooling is their achilles heel.

trecfive · « **Reply #24 on:** January 11, 2010, 15:08:36 »

If you think the rad is blocked, when you remove it fill it with cheap cola, and leave it overnight,the crap will get dissolved by the cola and float on the top by the hose mounts.I kid you not, i didn't believe it till i tried.

jkseries · « **Reply #25 on:** January 11, 2010, 19:48:32 »

Brilliant thanks.

The water leak seems to be coming from behind the water pump. There is another cover that is weeping. Off to see my not so helpful parts counter in the morning.

Now to find a new rad.

Thanks for all the help.

J

Disco_Dennis · « **Reply #26 on:** January 11, 2010, 19:51:52 »

If it's leaking between the water pump & block change the P gasket.

Use a metal one, not a cheapo composite or card one!

jkseries · « **Reply #27 on:** January 11, 2010, 20:16:08 »

Nope it's further back than that.

The water pump bolts to and through another plate before it reaches the block. I can't see it on the rave.

I guess I'll just ask at the counter

I bet it's the water pump housing.

J

jkseries · « **Reply #28 on:** January 14, 2010, 17:06:20 »

The new rad is on and cooling nicely thanks.

The thing that did occur to me was that there seems to be lots of places for air to get trapped in the system.

Has anyone found a cunning way of creating a new 'highest point' for all the air to sit in so it can be bled off?

Just wondering

J

mattyme · « **Reply #29 on:** January 17, 2010, 20:42:05 »

park your truck facing uphill on the steepest hill you can find and take the bleed plug out then. any air should find its way to the highest part.... the bleed plug.

with a bit of luck!! lol

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AuthorTopic: rapid overheating (Read 7975 times)

mattyme