Technical 1.1 Still Running a Bit Cold After New Thermostat?

[RayovacWorkhorse]

Hi all,

As title says, I've just replaced the (original) thermostat on my 1.1 after it started running cold about a month ago (was getting down to 1/4 on the temp gauge when coasting!). Now the freezing weather has set in, it is much better than it was, however at speed with the heater on it's still a little bit under the middle of the gauge, even after a 30 minute drive on the motorway! Is this just a panda thing or do I have a duff thermostat? Bought a febi 10897 if that matters.

 

[koalar]

Right where to start most cars this weather, if you put the heater blowers on full will drop the cars coolant temperature, Basicly you have a mini radiator and fan inside the car just the same as the one one the front

30 minuites on the motorway is should be hot, unless it's down hill or coasting as the injectors will not be firing.

Blower on speed 2, temperature on max red and just blowing at your face it should be pretty hot on the centre vents after 10 minuites or so. You can keep you fingers there but is more than just warm

If you stop and let it idle for a bit and the temperature drops at the vents , you have a serious problem that needs addressing immediately, Basicly the coolant is not circulating correctly, probably just an air lock or possibly a small leak letting in air.


If it's just warm at the vents and the same at idle, it's possible you have a fail on fit thermostat, if you have a scantool and log the temperature it should tell what the temperature it's getting to

Which thermostat do you have
Just thermostat or the thermostat combined with temperature sensor

 

[RayovacWorkhorse]

It's the "dumb" thermostat, pretty much only does it after a bit of coasting, when you put the power back on it comes back up within about 30 seconds, no running issues.

 

[koalar]

It's the "dumb" thermostat, pretty much only does it after a bit of coasting, when you put the power back on it comes back up within about 30 seconds, no running issues.

Are you sure it's not rev related

It's very important that its blowing hot at idle and stationary


If it's not and when you raise the revs to say 2000RPM it blows hot again you have a serious problem that needs sorting ASAP

30 seconds is far too fast for the engine to add enough heat

 

[Greasytrucker]

Sounds like a bit of a circulation problem doesn’t it

 

[varesecrazy]

It's the "dumb" thermostat, pretty much only does it after a bit of coasting, when you put the power back on it comes back up within about 30 seconds, no running issues.

Reply..

To me that doesn't sound 'wrong'..

As you are basically turning off the Heat Source ( sparks but no fuel..)

Whilst still pumping your Hot water through an icy radiator.. It's bound to chill a little

But.. If that's worse than a perfect @20 year old FIRE motor.. I don't know

 

[Greasytrucker]

TBH i’d be more concerned if it was running a bit hotter than it should be. Reminds me of my Dad putting tinfoil over the grill of his Escort in the winter to make the heater better!!!

 

[koalar]

Reply..

To me that doesn't sound 'wrong'..

As you are basically turning off the Heat Source ( sparks but no fuel..)

Whilst still pumping your Hot water through an icy radiator.. It's bound to chill a little

But.. If that's worse than a perfect @20 year old FIRE motor.. I don't know

This is correct

But @RayovacWorkhorse says it comes back hot within 30 seconds, far to quick for it to be from engine heating

Sound like the pump can not push the coolant over the u bend by the bleed screw unless the pump speeds up

Low coolant
Air lock
Blown head gasket
Blocked heater matrix

can all do this


Air lock and or low coolant is likely seeing as the OP has just fitted a new thermostat

The effect of the coasting should be seen on the temperature gauge

 

[koalar]

TBH i’d be more concerned if it was running a bit hotter than it should be. Reminds me of my Dad putting tinfoil over the grill of his Escort in the winter to make the heater better!!!

Unfortunately you can not rely on the temperature gauge, it's at the top in the cylinder head, an overheating engine due to air in the system will not always show on the guage as there is very little or no flow over the sensor

Which is why it can blowing cold at idle

I am not saying that's what's happing in this case

But it's why it need checking and if necessary sorting ASAP

 

[RayovacWorkhorse]

Heater is nice and hot once warmed up, regardless of revs, coolant is right on the mark, thoroughly bled the system with my fancy coolant funnel so I don't think there's any air locks. Might try an old school radiator blind! Once warmed up at idle it doesn't seem to do it. I'll continue to monitor it unless it gets worse/goes bang I guess, thanks for the feedback all.

Not as bad as my old 97 Celica at least, guage on that isn't going above 1/4 and the heater isn't exactly hot so I've snagged up a new thermostat for that one too! I swear my two cars keep copying each others issues!

 

[koalar]

Heater is nice and hot once warmed up, regardless of revs, coolant is right on the mark, thoroughly bled the system with my fancy coolant funnel so I don't think there's any air locks. Might try an old school radiator blind! Once warmed up at idle it doesn't seem to do it.

That's good

I'll continue to monitor it unless it gets worse/goes bang I guess, thanks for the feedback all.

Sensible

Not as bad as my old 97 Celica at least, guage on that isn't going above 1/4 and the heater isn't exactly hot so I've snagged up a new thermostat for that one too! I swear my two cars keep copying each others issues!

Which thermostat do you have

A

B

With the coolant warm but not hot and the radiator cap still on, if you slowly undo the bleed screw the pressure should push the last of the air out,

 

[RayovacWorkhorse]

That's good

Sensible

Which thermostat do you have

A
View attachment 434250
B
View attachment 434251

With the coolant warm but not hot and the radiator cap still on, if you slowly undo the bleed screw the pressure should push the last of the air out,

the second style of thermostat, and ye I've bled the air out via the bleeder both after the install, and after a week of driving

 

[koalar]

That's great

I have 1.1 and 1.2 with the older syle thermostat

In winter

A 3 mile drive from Crewe to Shavington, the temperature gauge was in the middle and the heaters were blowing hot

That on blower setting 1 to start off switching to 2

As far as I remember it does not reach half way and if the blower was on max the temperature drops on the gauge and out of the vents if you switched it to max once hot

 

[varesecrazy]

the second style of thermostat, and ye I've bled the air out via the bleeder both after the install, and after a week of driving

As important possibly :

Which method to swap the stat..?

Cap on and just swap the stat

Or pull a rad hose and drain the system

Leaving the cap on minimises the drain down.. So less air pockets after

 

[RayovacWorkhorse]

As important possibly :

Which method to swap the stat..?

Cap on and just swap the stat

Or pull a rad hose and drain the system

Leaving the cap on minimises the drain down.. So less air pockets after

read some past posts on here actually! kept the cap on tight, removed the coil pack bracket and swiftly swapped in the fresh one, lost very little coolant. with the "dumb" one at least there's no need to remove the battery tray, plenty of room to get it out by removing the coils.

 

[koalar]

I take it the coolants quite new

As it ages it becomes acidic and looses its anti corrosion properties 5 years is the max for the pink

As the car's get older the services tend to get missed

 

[varesecrazy]

read some past posts on here actually! kept the cap on tight, removed the coil pack bracket and swiftly swapped in the fresh one, lost very little coolant. with the "dumb" one at least there's no need to remove the battery tray, plenty of room to get it out by removing the coils.

That's how I did mine, on 04 1.1..the one in the GUIDES

I didn't see any cause for concern after..

But after all my previous HG issues I was handy with the bleeding routine

 

[RayovacWorkhorse]

I take it the coolants quite new

As it ages it becomes acidic and looses its anti corrosion properties 5 years is the max for the pink

As the car's get older the services tend to get missed

Fresh as of April yup, belt and pump done then, coolant was flushed at the same time.

 

[jrkitching]

For completeness, I'll just add that it's possible to reset the coolant's anti corrosion properties - you can buy an anticorrosion additive separately. Not something I'd do myself (changing coolant is no big deal for me), but perhaps worth considering for those not having the skills or facilities to do this for themselves. If you're on a tight budget, it's significantly cheaper than paying a garage for a coolant change and is better than doing nothing at all. Because the quantity you need to add is small, it can usually just be poured into the expansion tank without needing to drain anything, so doable without needing facilities by just about anyone.

Glycol based coolant doesn't lose its antifreeze property (unless you've topped it up with plain water, of course).

 

[RayovacWorkhorse]

For completeness, I'll just add that it's possible to reset the coolant's anti corrosion properties - you can buy an anticorrosion additive separately. Not something I'd do myself (changing coolant is no big deal for me), but perhaps worth considering for those not having the skills or facilities to do this for themselves. If you're on a tight budget, it's significantly cheaper than paying a garage for a coolant change and is better than doing nothing at all. Because the quantity you need to add is small, it can usually just be poured into the expansion tank without needing to drain anything, so doable without needing facilities by just about anyone.

Yup, good stuff for a stop gap, I'll always opt for a flush if i can though to get any bits out the system. When I got my old Celica the heater hardly worked, so I drained the coolant (which looked like gone off tomato soup!) and backflushed the heater matrix with a garden hose. Many, many chunks came out and it took a few flushes to clean the system out. After seeing that, my cars will always get their coolant swapped every 5 years