Technical Bravo TD thermostat problem

[LeeP]

My 1.9TD Bravo seems to have an intermittant thermostat problem. On most occassions the car heats up as normal and everything is ok but sometimes the heater remains cold and the temperature gauge rises to the red very quickly and the fan does not cut in. When this happens, I have to top up the water level with the 2 bleed valves open on the top of the radiator to expel trapped air. The car will then be ok til the next time. My first thought was head gasket failure but the oil is not contaminated, there's no steam and the car drives quite happily, just the other day I drove it 85 miles which it would never do with a head gasket blown. I'm now thinking that the thermostat must be sticking shut on occasions but I would have thought that it would either stick shut or not, not stick shut sometimes and open on others??
Can anyone help?
Also, anyone know where to get a new thermostat for less than the 50 quid I've been quoted (the best quote, the worst was nearly 90 quid!!)

 

[Hellcat]

£50 isn't a bad price... It's a lot of thermostat for your money!

 

[Stark]

http://www.shop4parts.co.uk/index.cfm/method/catalogue.list/
Best price i could find and that doesn't include vat or postage.

 

[jug]

if the thermostat was the problem how do you explain coolant loss. if you need to bleed air out occasionally there are only 2 ways the coolant could be lost, head gasket failure or a leak. either way the overheating problem (and loss of hot air at vents) is caused by a loss of coolant, and not due to the thermostat. look carefully for a leak at a pipe or the rad, if you cant find one get the cooling system pressure tested (and look for leaking when under pressure). fingers crossed it isnt the head gasket, but it could be. i've seen cars do hundreds of miles between bleeding the cooling system when the head gasket leak is very small, usually you can keep it topped up and drive it like that for a long time with no problems (just ask any rover owner)

 

[GTTD!!]

trust me, try this first.
Put two bottles of RADIATOR FLUSH into the system.
Run the car till the fans cut in, turn it off then pull off the bottom hose of the radiator, CAREFUL ITS HOT!
Stick a garden hose in the bottom hose and fill / empty repeat!
Now put the hose in the radiator and do the same.
Do this until the water runs perfectly clean.
Now fill the coolant system with clean water and run until warm again.
Once again empty.
Now reconnect everything tightly, and fill with 50/50 water and good quality anti freeze or summer coolant.
Remember to bleed the system of all air bubbles, if this doesnt work then take off your thermostat and drop it in a bowl of boiling water, if it struggles to open then youve found your problem.
Try WD40 or another anti seize formula and put some greese on the moving parts.

Sounds like a lot but its only a couple of hours work.
Dan

 

[jug]

i dont see how any of that can solve a coolant loss issue, if he needs to top it up and bleed it then there must be a leak or head gasket failure. where else can the coolant be lost and the trapped air come from?

 

[GTTD!!]

it used to happen on my SEIC and 306 dturbo, its when you fill it up sometimes air gets trapped and crud can block the thermostat or jam it, it worked twice for me and saved a fortune in garage bills,
Also the fiat engines are designed to run hot, the thermo doesnt open till 86 C, i drilled out the thermo holder unit and put in a 80 C one in instead, think it was from a 106, dont remember.
The coolant appears to go down because of the trapped air being heated and escaping through the pressure cap, only set to either 1.8 or 1.3 BAR i think?
I used to run mine with the cap off for about half an hour, topping up every time it escaped(which it does when you leave the cap off) this gets rid of any air for sure!
dont knock till you try!

 

[jug]

hate to sound bitchy but i think you've been drinking antifreeze.

when you fill it up sometimes air gets trapped

when you fill it up you bleed the cooling system to remove any trapped air. if any air appears after that it must have come from somewhere.

The coolant appears to go down because of the trapped air being heated and escaping through the pressure cap

at any given temperature, if the coolant level apprears to be lower than it previously was at the same temperature, there can only be 1 reason for that change, coolant loss. this is why its important to check the coolant level when cold. when hot it will apprear to be lower because water shrinks at a higher temp (not due to gas expanding and escaping through the cap)

I used to run mine with the cap off for about half an hour, topping up every time it escaped(which it does when you leave the cap off)

you're seriously suggesting that there's no need to use bleed screws?! this expains what happened on your cars. you didnt bleed the cooling system correctly. thats where the air came from. leaving the cap off wont get the air out. air travels up. if it was this easy to get the air out do you really think manufacturers would fit bleed screws?

there is no way a stuck thermostat can cause any air to enter the system, or fluid to the leave the system. only a cooling system leak can allow that to happen, where the leak occurs is uncertain, but thats the only possible way you can lose fluid and get air.

LeeP is topping the coolant up, so it must have gone somewhere, finding out where it is leaking is critical. if there was no leak how could he need to top up the fluid and where could the trapped air come from?

 

[stylers]

Antifreeze in coolant causes it to seek out leaks at pipe joints, which if there are any tiny leaks results in a very slow loss of coolant. look out for any white deposits at the pipe joints, especially on the thermostat housing and on the radiator itself. . if so its sometimes better to pull off the pipes and clean the mating surfaces of the pipes and fittings and refit, rather than just tightening..


Owen.

 

[GTTD!!]

You had this problem before mate?
You tried the above remidy?
Send me a picture of the bleed screws on a pre 1999 seicento, there arent any on some models.
YOU AINT TRIED IT, DONT KNOCK IT.

 

[jug]

Send me a picture of the bleed screws on a pre 1999 seicento, there arent any on some models.

very true not all cars use bleed screws, on models without bleed screws you would usually add a large pop bottle (or filler tool) to the filler cap allowing the fill level to rise above the highest point, this makes it possible for any air to rise out of the cooling system, but it is no where near as effective as using bleed screws and depends on a cooling system design that will allow air to rise to the filler cap area, limiting the hose arrangement possible, especially for the heater matrix. i would still not think it is possible to bleed these type of cars by leaving the filler cap off and running the engine, although i guess if you got coolant circulation going fast enough you could force a good amount of the trapped air back into the expansion tank, but this would still not be a good way to bleed any car's cooling system.
on models where bleed screws are fitted they must be used. if the filler cap is not the highest point in the cooling system it is virtually impossible to get all the air out unless you use bleed screws or pressure fill the whole cooling system.

YOU AINT TRIED IT, DONT KNOCK IT.

fair enough. i also havent eaten my own faeces but i'm fairly confident it wouldnt taste nice.

 

[GTTD!!]

ok, nice one mate. great forum, will definately not post here again.
only tryin to help,

feeky chucker.

 

[Stark]

ok, nice one mate. great forum, will definately not post here again.
only tryin to help,

feeky chucker.

Not posting here again? Well with your attitude i find myself very grateful for that, no-one on here appreciates a snippy tone in posts so that indeed is good news.
Happy posting on some other forum friend, try not to be as abrasive as you were here or you're likely to end up looking for another forum again!
If you knew anything you'd know all Jug does all day is help people! Without him there would be alot of people paying inflated garage fees......Including myself!
So in short, goodbye. You'll be missed about as much as my appendix was. :devil:

 

[jug]

ok, nice one mate. great forum, will definately not post here again.
only tryin to help,

feeky chucker.

sorry to cause offence. i'm only disagreeing with you based on my own experience, i'm not trying to insult you. cant we agree to differ?
there's no need to blame the whole forum for something i said. if you own a fiat this forum is very useful, just ignore me.

 

[Venters]

sorry to cause offence. i'm only disagreeing with you based on my own experience,

I really can't see what you have to say sorry for. He only said he won't post again. So he will be back on to take advice. Only won't put any info back.
Proberly be saved loads of money aswell and never donate!


But this leak is it bad how often do need to top up. Is it regular?

 

[GTTD!!]

I really can't see what you have to say sorry for. He only said he won't post again. So he will be back on to take advice. Only won't put any info back.
Proberly be saved loads of money aswell and never donate!

Hi there, you joining in?
Do people not want any help?
If you fcuk people off, they won't help.
If i pay FIAT £300 to sort something out, just to find out the problem was an easy fix... then you get the same problem and i don't say a word...

Thats why i said wont post again...

You see, everyone is nice, everyone gets help...

Nothing i can say which someone wont retaliate to it seems,

Oh well, hope i can help someone...

 

[Venters]

Hi there, you joining in?
Do people not want any help?
If you fcuk people off, they won't help.

Exactly! Jugs helped more people on this forum than most people can count to.

If i pay FIAT £300 to sort something out, just to find out the problem was an easy fix... then you get the same problem and i don't say a word...

Thats why i said wont post again...

You see, everyone is nice, everyone gets help...

Flushing a system won't stop the coolant loss!

 

[ryann143]

alright mate. you said that you opened the 2 bleed valves on your td can you describe where these are? i think i have anairlock but cant find the 2nd bleed screw-have found the one on the rad

cheers

Ryan