I've read a lot of the threads on here regarding thermostats, cooling system, etc., but haven't quite got a handle on what my own Punto mk2 1.2 8v is doing. Have a pretty clear description from yesterday's driving patterns (on a rainy day, around 7C ambient)

1. Temperature slow to rise generally.
2. In sustained idling (traffic jam) temp gauge goes to 50% and holds there.
3. When driving at speed (e.g. 90kph, sustained) temperature drops down to just 1/8 above min. This happens pretty quickly (so bad thermal cycling perhaps, and need to so something about this).
4. Cabin fan heaters do a decent job of heating the car, apparently whether driving or in standstill.

I was planning a bunch of work on the car over the holidays based on parts I've ordered:

1. Replace timing belt and tensioner
2. Replace water pump
3. Clean throttle body
4. Replace spark plugs and HT leads
5. Renew coolant
6. Replace alternator belt
7. Perhaps replace thermostat (I thought the car was just failing to heat up at one stage -> jammed 'stat)

Apart from 7, most of this is just because it hasn't been done for a while, or I don't know how far back was last done.

So, on action-7, do folk think that my symptoms fit with a bad/suspect stat? What would be the most likely/common-place explanation be for the engine temperature behaviour? (I'm guessing not gauge since it does go between 0 and 50% fairly easily).

Cheers!

Hello,
YES - it does sounds as if your thermostat may not be closing completely,
for the trouble of removing it you may as well install a new replacement,

be careful on "bleeding" the air from the system as you refill with Paraflu / coolant,

Charlie

Sounds like thermostat is jammed open. As Charlie has said I'd replace it, but only with a new genuine part from Fiat. Far too many dodgy ones floating about on the market.

go to an iso registered motor factor and buy a thermostat ,gates sell quality so buy one of those it will be approx £17 to a punter,it comes with thermostat,new gasket,new thermostat housing
leave your radiator cap on and you will lose less than a teacup of water out of the system so a full bleed and a dance on one leg whilst singing marry xmas everybody is an uneccesary action

do NOT buy from the internet

look here for guidance
https://www.google.co.uk/#q=fake++copy+brake+pads+in+northern+ireland+trading+standards

Fairly certain the stat is lazy. The temp should be up to the middle after a few miles of open road driving and stay there all the time - none of this creeping up to the middle at a standstill in traffic or falling back at speed.If anything it should tend to go slightly over the middle in heavy traffic until the fan cuts in.As the car has been running cool, now would be a good time to check the fan. With the car stone cold see if it turns without squawking or scraping and with the engine running you could disconnect the temperature sensor to see if the fan comes on. This will give the red temp light on the dash and the yellow eml lamp which will go away after the next two or three trips. As has been said already beware of the Kan-Do-Hot Trading Co. stats. A lot of people have been caught out and have replaced two or three in a short time

my car would loose heat when traveling, sat at idle with the fans on

Used to take ages to heat up as well

Fitted a New Genuine Fiat Stat - From an Ebay shop - cost about £15

Happy laddy

Bleeding can Yes be a PITA....

Ziggy

s and b said:

go to an iso registered motor factor

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Don't mean to pump you, but iso registration is not a guarantee of quality products.

It only guarantees that quality systems are (nominally from my experience) in place.

Otherwise, wholeheartedly agree with the spirit of the post.

Brendan W said:

As has been said already beware of the Kan-Do-Hot Trading Co. stats. A lot of people have been caught out and have replaced two or three in a short time

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I will try to get original FIAT stat tomorrow. What I'd planned to buy was what the local motor factors have, which is from quinton hazell (qth275k). How much of a liability is that likely to be?

The shop4parts recommendation is by "original birth"

Q+H are what i brough from halfords and from a local auto shop

Both didnt work that great for me....

Got mine from here

Same sorta price i paid from auto parts places inc halfords

Ziggy

QH are now essentially Chinese, said to have has fair few QC issues. Allegedly now sorted.

fingers99 said:

QH are now essentially Chinese, said to have has fair few QC issues. Allegedly now sorted.

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theres a story to quinton
unfortunately they were bought out by klarius but they went bust a year ago
the shell name quinton hazel was bought by the company tetroseal ,group companies include Tetrosyl CarPlan International Carlube Aqua-t Bluecol Tetrion Tetconnect T-Cut Triplewax
unfortunately qh products have been in my opinion rubbish for the last 20 years,last thing i got delivered by my factor was a punto handbrake that promptly pulled through the backplate and was returned as what it was rubbish

i wont buy qh again until the new company prove their products are now quality

this is why i recommended gates

Thanks for all the tips on parts. Hopefully it's a common enough part that the fiat place will have it in stock and not too dear. I'm maybe lucky I didn't get to the factors yesterday, having gotten delayed with Christmas shopping.

I'll need some jubilee clips too won't I? Any special requirements there, or can I go to local hardware shop?

Col Max Pyatnitski said:

Thanks for all the tips on parts. Hopefully it's a common enough part that the fiat place will have it in stock and not too dear. I'm maybe lucky I didn't get to the factors yesterday, having gotten delayed with Christmas shopping.

I'll need some jubilee clips too won't I? Any special requirements there, or can I go to local hardware shop?

Click to expand...

Dont buy Halfords Jubilee clips - there weak and made of cheese
i've got some B+Q clips and they seem to be holding atm...

IF you are unsure of you concentration or age of the old coolant, i advise when you drop the coolant, you do a flush

Ie - fill with Distilled water - run the car to allow it to circulate and then drop it

Then refill with a nice strong mix
I tend to wack 1L neat in first, then mix any remainder in thats a 50/50 mix

Fresh coolant = Happy cooling system

Ziggy

If you're dumping it, I'd not bother with distilled (unless you live in an extremely hard water area!). Factors will sell you a bottle of radiator flush for 3 or 4 quid. Well worth using that just before a coolant change.

fingers99 said:

If you're dumping it, I'd not bother with distilled (unless you live in an extremely hard water area!). Factors will sell you a bottle of radiator flush for 3 or 4 quid. Well worth using that just before a coolant change.

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i did the same used tap water when i did my coolant change a few days ago

Yeah. After umpteen years I'm just moving to the 5 year stuff and de-ionised. But in the civilised world, it's probably just a luxury.

benny279 said:

i did the same used tap water when i did my coolant change a few days ago

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i prefer to use fresh tap water rather than used
did you bathe in yours first then

s and b said:

i prefer to use fresh tap water rather than used
did you bathe in yours first then

Click to expand...

I live in a non hard area for water so it ain't too bad. Cars been running great since coolant change and new brakes

Just to update, I got the thermostat part and finally fitted it yesterday. Broadly speaking a pretty straightforward job, prising off the factory-fitted hose-clip was a bit of a pain, but otherwise no big deal.

I know the recommended way to determine if a stat is working or not is to boil it and see if it opens, but I didn't bother with that as I'm getting a bit of a mechanic's sixth-sense I think, as I quickly had the certain insight that the original thermostat wasn't operational... you can see the attached thumbnail for yourself.

No idea when the thermostat was last interfered with, but given that it was a lancia-marked part and the factory hose-clip was on, I'd say it was the original component.

Anyway, I haven't had the car out for a proper drive yet, but was out into city today, driving for about 45mins, and the temperature climbed relatively quickly to 50% and held steady. If it holds when doing speed on the motorway, then I'll say the temperature anomalies are solved. Have to see how the fuel efficiency changes too, hopefully for the better (one would expect).

Thanks again everyone for all the tips, advice, and reassurance.

No stat was to usually cover up an overheating issue like the fan not working....

There is also some fur which says to me that stat seal has leaked in the past....

Keep an eye on fluid levels, temperature guage as well

Enjoy cabin heat!

Zuggy