Thread: TDI300 overheating and air lock woes - any advice?

Hi All

As reported on another thread, I have just experienced a over heating episode, so now there is another brand new water pump installed into 'Fred', the last one has lasted less then 10,000 Klm's, is the heat killing these pumps?
I did catch this one in time, with only a slight drip from the weep hole, but the bearing is defiantly is noisy and on the way out.

Does pump cavitation cause these symptoms and then sets off a chain of events?
Air or combustion gas makes it's way to the pump, combined with a hot day and a constant load, the pump looses it ability to keep the coolant flowing.
The resultant cavitation causes over heating to occur, then wrecks the plastic cage around the bearing, that then allows the shaft to wander out of alignment causing the seal to leak.

I did check in through the radiator plug hole and looked for any signs of blockage in the core, it didn't look as bad as I was expecting, but I will be installing the new radiator that I have on order from 4 Wheel Drives in Blackburn, I am taking the old radiator home and I will be rodding it out to find out how blocked it might be.

Is there a air baffle missing from under the front of 'Fred' ?
I looked under the nose and if there was a baffle between the lower portion of the holes in the bumper up to the front cross member that would help the air flow through the radiator.

The tell tale spots of dry coolant under the water pump housing are a warning to change the pump and are not to be ignored!
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Has anyone any details and brands of low fluid level alarms, and the coolant alarms and the best location to mount on a 300tdi?

http://www.aulro.com/afvb/discovery-...t-warning.html

Dave's Interesting Things - ESSLR2

Dave (not the dave selling)

Originally Posted by stumps

Raw flow from the high point of the thermostat housing (upstream of the stat) flows to exp tank via the Y piece device. This has an internal venturi. So, not only is vapour purged to the exp tank by this raw flow, but the low pressure zone created by the venturi will 'in theory' also suck in to the exp tank vapour that has got into the radiator top. Simple and effective maybe?..but appears to block easily on the raw flow side (as mine was found) thus then becomes useless!

Wow was mine was blocked today! used a drill bit to clean the plastic housing out and then shifted the rubbish out of the pipe with a good blow, its possible to check this device insitu by undoing the pipe from the thermostat housing end only and then blowing through it, with the pipe into radiator held tight that diverts all the air to the header tank, if the path is clear you can hear the air bubbling inside the header tank and then repeat for the pipe going into the radiator, while squeezing the header tank pipe closed.

I also noticed there are no valves in the piece.

no valve, it's a venturi.

So with a new water pump installed and the air purge device cleaned out, away we went. Leaving Apollo Bay then travelling along the coast on the Great Ocean Road to Warrnambool, then across country via the B120, past Dairy farms and colourful paddocks of Canola to where we are camped in style in a onsite cabin at the Lake Bolac Caravan Park.

How's 'Fred'? ask's the Wife every couple of klicks, 'Fred's' fine I would reply, He's at nine o'clock at the moment, then came a long pull uphill, "How's 'Fred'"? I would reply Hmm! he's at 10.30 and climbing, I think we had better pull over and cool him down, and so on it went for our trip.

But we only had to stop twice on the way extra to the sight seeing spots, where we entertained the locals with the antics of yours truly spraying the top of the motor down with a pressurised 5 litre garden spray.
The B double bloke, I wonder if he will get over it, he did wobble his rig down the road trying to get a better look in his mirrors! The radiator will definitely be changed for the new one when we get back to Melbourne, I am one hundred percent sure 'Fred' wouldn't make it up Spring Hill with the loaded car trailer when I get back to Tassie on Sunday.

The water when sprayed in, evaporated quickly from the top of the motor but not from the radiator tanks, that to me is proof that the radiator is badly blocked.
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Once a standard defender temperature gauge moves from its normal resting place you are up over 110 degrees Celsius.

They are not a gauge but an indicator

Effectively they do not move in a range from 60 -110 degrees.

Im thinking like JC a blocked radiator wont create pressure in the water jacket - HG is suspect.

Dont stress too much though, before I changed out my old tired engine it would regularly run to 125 degrees but I would not let it get any higher - just backed off and took it easy... drove it like that watching things carefully until I was able to do the engine swap. On inspection the fire ring was gone on all 4 pots.

S

It's possible that the new head gasket installed 3000Kms ago has let go due to a manufacturing fault.

I had the head gasket done (and head resurfaced) after a small overheat on my 97 300TDi and within a few thousand KMs had air bubbling back through the expansion tank again.

My mechanic (Sovereign Motors) pulled it apart again and discovered that the HG they used had delaminated (I think). Don't think it was a Genuine LR one. They put in another one, at no charge to me thankfully, an it's been fine ever since and that was 5 years ago. The 2nd HG was a genuine LR one.

Originally Posted by spudboy

I had the head gasket done (and head resurfaced) after a small overheat on my 97 300TDi and within a few thousand KMs had air bubbling back through the expansion tank again.

The first thing that I will be checking for this morning, is the tell tale bubbles in the cold coolant.
No bubbles present will mean that my tactics of driving slow on the back roads has paid off ------- for the moment!
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Thanks to all for advice and experiences...well yep it was the head and gasket. Reckon some poor installation done as no dowel pins in there..inlet valve not seating properly and a few other things..head needed some facing too from cooking it seems.

Now running nice.
ps...never realised how easy it is to bleed the coolant system now I have no gas entering!

Will definitely add some further monitoring devices when I can get $$.