Series 3 2.25 diesel - running temp with snapped fan belt

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WoodyO

Well-Known Member
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330
Location
UK
Afternoon all,

Out for a drive on Saturday morning when I heard a thump and my charge light came on. Knew immediately it was the fan belt letting go so pulled over and let the engine cool for 30 mins or so.

Luckily I was only 15 mins from home so set off again gingerly, heating on full whack in an attempt to keep it cool.

My needle usually sits around 1/3 on the temp gauge, running all new coolant system; hoses, matrix, radiator, thermostat, etc.

I was quite surprised to see that the needle crept slowly up to around 2/3, just about hovering over the top of the N on the gauge, but then steadied and didn't budge for the last 10 mins back home.

No signs of over heating when I got back, wasn't boiling over etc, so I'm happy the gauge is accurate enough and hadn't just topped out.

Quite nice to know if the worst does happen I'm not going to cook the head immediately.

I now carry a spare.
 
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The time an engine/head really cooks is when the coolant has gone, even when there is only a bit left still turning to steam the temp will not be much more in the engine but once all gone the temperature sky rockets. The fact that your engine was already warm helped through thermal convection.
There were some aero engines in the 30's that were steam cooled to save weight but a leak would release high pressure steam, not good when you are sitting behind the motor.
 
I carry a spare fan belt with me as my engine is 200DI and would not like to risk overheating and damaging the head.
 
Agreed, thermal convection and a decent heater matrix saved the day, I'm just quite surprised how stable the temperature remained.
 
Agreed, thermal convection and a decent heater matrix saved the day, I'm just quite surprised how stable the temperature remained.
At the sender only though? I would still be wary that the water wouldn’t be moving anything like when it’s pumped and you could get localised hotspots that may not register on the sender and gauge
 
Quite possibly, but no signs over overheating at the expansion. I'm certainly not suggesting doing it or going to keep running it like that, just an observation I thought I'd share.

Although I'm sure there would have been hot spots, I can't see the temperature in a common water jacket varying enormously.
 
Are cast iron blocks and heads less likely to be damaged by overheating if spotted quick enough?

I have read that it can be too late for aluminium engines by the time the gauge even moves.
 
I haven't ever seen many threads about overheating damage to four cylinder petrol or diesel Series engines on here.

Are these engines not known for it?
 
I haven't ever seen many threads about overheating damage to four cylinder petrol or diesel Series engines on here.

Are these engines not known for it?

not really being cast iron. The trouble arises when you have a cast block and an ali head - different expansion rates which is what causes the warpage
 
Years ago I bought a Triumph 2 litre, affectionately known as the shark nose cos of the shape of the front end. I bought it on a bank holiday in the days when nowhere was open and I had to drive it 25 miles home. It started overheating within a coup!e of miles, it turned out a core plug had corroded away. I stopped to let it cool then drove another few miles, I repeated this a couple of time till I got home. The engine was super hot but the head survived. Old engines are bomb proof compared to modern stuff.

Col
 
Knew a chap who when 9 or 10 was given first tractor job by his farmer dad of chain harrowing a field driving a Marshal tractor, the old type that had just one cylinder and ran with a distinctive Pop bob pop bob sound.
After an hour or so his dad came back to check on him and as he came nearer was shouting and waving for him to stop. The tractor had lost all water and was so HOT they could see the shadow of the piston and rod going up and down in the block !!!:eek: They let it cool and then fixed the leak and it went on to work for many years.
 
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