Advice please: engine running cold, long drive coming up

[fucthest8]

Oh urban petrol heads, forgive me, for I am Not Very Mechanically Well Educated.

Engine's running cold. Diesel. Op temp is 90, doesn't make it much past 80 and if I go long distance (or, sometimes, just down a long hill) drops to 70. Heating in the cabin i s really variable. Worked this morning just fine, the other day, not at all.

Started going wrong after a very long period stopped/crawling along the A303 past Stonehenge (3 hr journey to my parents palce took 6 hours).

(a) Thermostat, right?
(b) If I drive it 300 miles, will I be doing horrible things to the engine? Have a trip coming up Friday.

Fanks.

 

[passenger]

It could be the heating matrix or thermostat.

 

[Sprocket.]

If your thermostat is not operating and opening it will cause your engine to overheat and could possibly blow your head gasket at least.
I’d advise to get it checked. In past times I have run cars through winter without a thermostat in. Your engine circulates coolant but your heater will only get lukewarm after many miles.

 

[DownwardDog]

Check it's got adequate coolant in first. If it has then the thermostat is probably fucked.

Yes, it will do horrible things to the engine. It's not the fact that it's running slightly cooler but the bearings will be getting fucking thrashed on start up as it will take far too long to warm up.

 

[fucthest8]

Cheers all, getting it checked tomorrow anyway, but they're really busy so it may not get fixed in time to set off on Friday ... was wondering if I could drive it anyway or if I should hire something.

In past times I have run cars through winter without a thermostat in. Your engine circulates coolant but your heater will only get lukewarm after many miles.

Yes, it will do horrible things to the engine. It's not the fact that it's running slightly cooler but the bearings will be getting fucking thrashed on start up as it will take far too long to warm up.

So you can run it ... but shouldn't?? I already drove it 160 miles at 80deg ...

 

[Sprocket.]

Modern engines are run to quite specific tolerances, the cooling system attempts to allow the engine to run efficient as possible. Bearings and moving parts rely on temperature being maintained in a narrow band.
It could be quite an expensive trip. I, myself would see what your mechanics say, but I would probably hire something, it will possibly be cheaper.

 

[twentythreedom]

Gaffer tape on the rad to limit cooling

 

[Sprocket.]

Though being totally honest I have spent and spend far more hours working with these little beauts than car engines.

 

[Santino]

Carbon on the valves?

 

[Duncan2]

just possibly you may need to bleed air out of your coolant e.g if there is a slight leak somewhere.

 

[kebabking]

Dunno about the specifics - because, you know, I'm a generalist rather than trade - but id not be doing a long journey in cold weather in a car with an engine problem.

Hire something.

Sounds crassly like 'just spend money', but having a problem at 70mph on a dark motorway is not fun, the RAC/AA could take several hours to get to you and your engine could be a right off - all of which would make the cost of a hire car look like pennies..

 

[peterkro]

Gaffer tape on the rad to limit cooling

Cardboard in front of radiator is traditional method.London cabs often have a special little jacket on outside air inlet.

 

[dessiato]

I've had this problem for several years. If it's running cold it's because the thermostat is stuck open.

 

[Sprocket.]

I've had this problem for several years. If it's running cold it's because the thermostat is stuck open.

Or because the thermostat was removed after jamming shut and the engine overheating. Like I had happen with a number of Fords in the late seventies/early eighties. Having to carry a half inch AF spanner and a bottle of water at all times. Always seemed to happen at busy level crossings.

 

[Poi E]

Good old days. Line up of men swearing at their sputtering shitboxes in the morning as they sprayed the points.

 

[dessiato]

Or because the thermostat was removed after jamming shut and the engine overheating. Like I had happen with a number of Fords in the late seventies/early eighties. Having to carry a half inch AF spanner and a bottle of water at all times. Always seemed to happen at busy level crossings.

I still carry a bottle of coolant, just in case.

Good old days. Line up of men swearing at their sputtering shitboxes in the morning as they sprayed the points.

And early Minis with crap carburettors which would freeze in the right conditions.

 

[Sprocket.]

Good old days. Line up of men swearing at their sputtering shitboxes in the morning as they sprayed the points.

Whipping the spark plugs out, putting them on a bit of tin foil under the grill.

 

[A380]

Whipping the spark plugs out, putting them on a bit of tin foil under the grill.

Spaying a can of ether in the air filter. Can’t rember what it was called?

 

[dessiato]

Spaying a can of ether in the air filter. Can’t rember what it was called?

Something like Quick Start I think.

 

[DownwardDog]

Spaying a can of ether in the air filter. Can’t rember what it was called?

Brake cleaner also works, just don't inhale the fumes.

 

[Sprocket.]

I could relate a tale of three men in an old Sierra diesel, in France with a minimal few words of French. Trying to buy a can of easi-start!
It involved one of my mates miming turning an ignition key, going Rrr, rrr,
While my other mate pressed on the top of his head with his hand and bending his knees, going psst, psst!
Luckily a passing German translated with ease what we required, besides French lessons.
ETA: This was thirty years ago, our French is still abysmal

 

[mauvais]

I've had this problem for several years. If it's running cold it's because the thermostat is stuck open.

This. Modern thermostats fail open.

A replacement is typically about £100 fitted.

You may also find that the dashboard dial isn't linear, e.g. the middle is 90, and it supposedly starts at 50, but 25% is more like 85 than 70. You'd need a diagnostic device to be sure.

 

[DownwardDog]

I could relate a tale of three men in an old Sierra diesel

My mate's dad had one of these with the 2.3 NA (none of your turbos here, this was the mid 80s) Peugeot diesel. It had no power (about 60bhp) but loads of torque and was a drift monster in the rain. It was a very strange car and I wish I had one of the estate versions.

 

[Sprocket.]

My mate's dad had one of these with the 2.3 NA (none of your turbos here, this was the mid 80s) Peugeot diesel. It had no power (about 60bhp) but loads of torque and was a drift monster in the rain. It was a very strange car and I wish I had one of the estate versions.

That’s the model, hours of fun and stress!

 

[fucthest8]

This. Modern thermostats fail open.

A replacement is typically about £100 fitted.

Yep, it had.

£90 all in, managed to get it fixed on the Thursday