(T) Engine running hot and lack of hot air in cabin

Engine temp is climbing to the top white line, and there is no hot air from the footwell blowers.

Airlock in cooling system I assume?

Top rad pipe is hot, lower one is considerably cooler.




I thought I had bled it completely last weekend....

Sounds like a blocked radiator, or a major blockage somewhere else in the cooling system. The top hose comes from the thermostat and feeds hot coolant from the engine into the radiator, where it is then cooled and fed back into the engine via the bottom radiator pipe. The bottom pipe then feeds the coolant to the water pump (via the metal pipe) and it is then circulated back round the engine. Therefore if the top pipe is hot and the bottom pipe is cold it suggests that coolant isn't flowing through the radiator correctly. It could also mean a failed water pump, which may explain why heated coolant isn't being fed into the heater matrix.

Additionally it could mean a massive airlock like you suggested Ucof. I think there are two bleed screws, one on the radiator and one near the heater matrix pipe at the bulkhead. Did you bleed the system from both of them? Also, did you change the thermostat? Another possibility is that the thermostat is sticking shut, but they are still designed to let a small amount of coolant through even when closed. That may explain why the top pipe is getting hot from the small amount of heated coolant that is coming through and why the bottom pipe is staying cool.

I'd do the following, in this order, until the problem is eliminated:

1. Bleed the cooling system again
2. Replace the thermostat
3. Reverse flush the radiator/ cooling system
4. Change the water pump

I suspect 1 and 2 may solve your problem!

Good luck,

Chas

Cheers for that


There's a guide around somewhere explaining how to test the thermostat isnt there?

If you're going to take it off you may as well replace it with a new item. They're not that expensive

They are for me at the moment
I'll have a look on the yaBe.


mumblegrumblestupidcounciltaxandrentandbillsandfoo dandpetrolmumblegrumble.

actually, this one is cheap - http://cgi.ebay.co.uk/FIAT-UNO-60-1-...item5886b9c979 - that'd fit wont it?

If it's the one they've pictured, then no it won't. The Uno FIRE thermostat is integrated into the thermostat housing and comes complete as one unit. It is possibly to change just the thermostat itself and reuse the housing but you need to modify it to do so. It was a popular modification amongst the 'Cento Sporting owners so they could fit cooler thermostats to combat hot running issues. I think there's a guide in the 'Cento section so have a look there.

Otherwise just buy a new one. Remember, a jammed shut thermostat will cause the engine to overheat. Dealing with a blown head gasket is going to be a lot more expensive than replacing a thermostat

Don't forget to try re-bleeding the cooling system first though, that might solve the problem!

Ah righto. Thanks again.



Then this'll do I think - http://cgi.ebay.co.uk/THERMOSTATS-KIT-FIAT-UNO-1-0-1-1-1-3-1987-2000_W0QQitemZ250516696842QQcmdZViewItemQQptZUK_Ca rsParts_Vehicles_CarParts_SM?hash=item3a53f56f0a - note that the picture is not what I'd be getting.... which is a bit stupid really.

Just a thought - i dont think the fan is kicking in automatically anymore either.... how do I reset the ECU again? Disconnect the batter for 30 mins, then reconnect and run the engine 'til it kicks in??

Bit daft to show a picture of a different thermostat to the one they're actually selling If they say it's for an 1108cc FIRE in the years quoted then yes, it should be the right one.

Fan not kicking in - have you checked the fan actually works? Have you tried wiring 12v directly to it? Might be the fan switch on the radiator also?

As for resetting the ECU, I think that's what you do. I'm not that familiar with the later mk2 SPi system, sorry. It's been Weber carbs all the way for me!

To add to the above,

Think the Uno can sometimes get air locked even when bleeds are open. tail tail sign is that the system appears full after about only a liter of water .

can try blowing into the rad cap hole (when cold) and or squashing the top and bottom hoses in situe.

How long has it been run for since the last time you flushed it? a few mins at idol or revving past say 4K rpm? has it been OK since, and then gone bad?

was thinking knackered pump too but would there be any hear past the thermostat

to test the fan, there is an electrical plug at the bottom of the radiator which is fixed into the rad temp switch. pop the plug off and attach a wire between the pins to bridge the gap (leaving the swith in the rad). be ware as the fan should instantly come on and stay on till the wire is removed - don't get tangled up in it or fingers chopped off .

Good luck!

As the Chuckle Brothers would say:
Oh dear, oh dear, oh dear...

Temp needle hit the red on the way home today so I stopped off and popped the bonnet. First thought: bleed the system.
So I undid the screw up near the bulkhead.
Psssssssssssssssssssssssssssssssssssssssssssssssss ssssssssssssssssssssssssssssss....
*carries on hissing*
*continues to hiss*
*doesn't stop hissing.


Opened the res cap, to be met with the sight of lots of steam...and not much water. Thankfully I went to the nearest shop and bought a 2.5 litre bottle of Evian water. Returned to the car and topped it up, then got home without any major issues.

Parked up at mine and instantly filled the res tank full, started the engine and continued to bleed the system.

Water level in the tank continued to drop.
I looked into the engine bay, and saw a constant long dripping of water, from between the exhaust manifold and the cat

Have I actually got a knackered HG this time?

Water is clearly escaping in floods, and there's also a lot of steam that comes out of the exhaust when I rev the car.



On the plus side... I had hot air coming out of the vents in the car whilst there was water in the system.

I think I'll be getting the compression tester out tomorrow if it has stopped raining...


Just found these useful links:
https://www.fiatforum.com/uno-guides...-cold-uno.html - in the Uno guides section.
http://www.aa1car.com/library/coolant_leaks.htm

Never ever take the rad cap off when the car is over heating. no car is woth it!!

your lucky that there was not much in it, of you'd be in hospital with serious burns, and lifetime scarrs cos it sprays out with force and is verry hot. I have seen the results when I was a kid - nasty!!

Sounds like the engine may have got so hot that the head has warped (bent) if you have been into the red.

compression tester won't tell you if the head gasket has gone if it ain't gone into the bore (leaking engine gas) out .

you want to try and trace the water leak... Oh you found it in guides.

it may be one of the pipes at the back that has split, causing the water to fall out

Think I still have a 999cc head (can't remember if I kept one) incase your is bananna shaped now.

You need to find the cause of your problem which may have resulted in HG failure / split pipe (faulty fan switch?? bad water pump) before you fix the symtoms, or it will just go again

Cheers for that Louie.

Regarding the rad cap, I had already let all the pressure out via the bleed screw so the system was not under pressure. Or is this not the issue?

I'll be under the car tomorrow then trying to trace this leak.
What happens if it is just leaking into the engine and coming out of the exhaust pipework?

I know the fan has worked since I got the car though... it could just be bad luck that it has failed now.

Just cos the fan wasn't on today don’t mean it's not functioning as it should...

Like the in car heater, there needs to be enough water in the system to circulate, and it needs to be circulating for both to work work.

But if no water in, or water not circulating neither will work. The rad fan switch is at the bottom of the rad where you said was cold today, so the switch will not have seen high enough temp to cut in it don't know how hot the head is as it's not linked to that temp sensor.

So the fan switch rad fan may or may not be working, but either could have caused a HG failure as could a faulty water pump, blocked radiator, air locked system, split pipe, leakey rad cap (or other leak in system).

But the HG may have simply failed due to system neglect and caused the water to be lost and the other symptoms follow.

If copious amounts of steam/ water is now coming out of the exhaust then you almost certainly have a shagged head gasket

Louie has already covered most, if not all, of your current issues. You have a choice of replacing the head gasket or replacing the engine. Considering the amount of work and costs required for replacing the head gasket, it might be an idea to consider an engine swap for a known good engine. You could even upgrade to 1242 status while you're at it!

Personally I'd go for the engine swap as it's likely to be cheaper than a head gasket change and associated parts/ machining, though obviously you'd need to remove the engine and drive-train to do this. Punto 8v 1242 engines can be picked up for not much at all these days, figures like £60 for a lowish mileage lump are not unusual. Swap a few pulleys/ mounts over and there you go, one 1242 Uno