Any advice greatly appreciated!

My Fiat Punto 80HLX 16v(year 2000) was idling a bit roughly when I pulled up after a 50km trip on open roads. Upon popping the bonnet there was a very thin stream of coolant coming out the top of the expansion tank cap.

I let it cool over-night. Checked fluid level - half way between low and high. Started it up. After 5 min the thermostsat opened sending water into the radiator and seemed to be circulating fine.
Took it for a run - fine at 80-100km but on crawling along for 5min at 40km the temp shot up. Pulled over, cut engine, ignition on - fan going until temp was back down - no coolant leak this time and level good.
Got home and have been tinkering to no avail.

Drained coolant - good condition. Flushed radiator - no rust flakes or brown water.
Connected it up and bled system.
Started it up without cap on. Idling smoothly. Surging in the expansion tank with some bubbles, but settled down as the fluid moved through. Bottom hose off radiator warm. It heated up above normal and fan didn't come on.(maybe I needed to wait a bit longer for fan cut-in)
Tested coolant temperature sensor by disconnecting - fan went on.

Could it be the water pump has failed? (has done 180,000km)
Could it be head gasket? ( But - no sludge in oil, no water in oil, no coolant loss)

I'm a bit clueless so any info appreciated.

Hi.
iwouid change cheapest part first. (Thermostat)
it may be sticking.

is there any white residue on oil cap or Dipstick.?
also when cap is off radiator and engine running see if there is any white frothy bubbles
if so headgasket may be on its way out,.
they fail in different ways so its hard to take aguess, Preasure test might be the way forward if the problem isn't thermostat related.

Do you hear any Gurgle noise from heater when you first start car?
that might indicate an airlock if so,.

These punto's are awkward to get airlocks out of the coolant system.

YES..Airlocks and Thermostats are the most common issues..,

along with seized / inop. fans= but you're o.k. there..!!

your water pump should either work / or NOT as it's driven by the cam-belt,
sounds as if it's circulating water around the jacket o.k.,

it's pointing towards a bad thermostat to me,

cheap + easy fix.., it comes as an assembly = stat. in housing, fresh coolant would be a good idea too,

good luck with the bleeding..!!,
Charlie

No residue on cap or dipstick and no frothy bubbles in coolant.
I would have thought that if I'm getting the radiator hoses heating up the thermostat must be opening up ok. Or could it be an intermittant fault??
Have to see about sourcing one - fiat parts low on the ground over here in NZ.
Thanks for your help

Just remember sometimes you may get a mayo residue on oil cap usually caused by someone that only does short journeys this is caused by condensation, nothing to worry about though.

You can test you're thermostat by removing it from the vehicle place it in a saucepan with water and cook it you'll see it open , once you do remove it carefully from the saucepan place it somewhere safe and watch it close if it fails to close then you've found the culprit.

If stat is fine put it back on the engine, and look at other possible culprits as mentioned airlocks if latter then go in the guides and look for the bleeding guide for 8v/16v.

Hope this helps.

Benny

I would do a compression test. It's the only sure way of telling if the head gasket has gone. Rough idle is often a sign.

iagree, get a test done.


Btw don't try to run these 16v engines long if there problems with cooling
you will cook the cylinder head.

they is expensive to put right once they go pear shaped.

Ok. Sounds like I'll need to find someone to do a compression test - don't have the tools or know how to do it myself.
Thanks for the help.

i think you are right with a failed impeller on the water pump
these are made of plastic too so can go
ive got some pictures somewhere in photobucket of one i had

easiest way to confirm for a layman is to remove the water rail in fronyt of block and look in the hole

as said dont run engine until sorted ,the one i had had been and been cooked to kingdom come

Thanks
Do I need a new seal gasket upon re-assembly? (It's a bugger living 100km from the nearest parts place - and even then they'll probably have to order it in)
Does the rail just slide out once the single bolt on the bracket is removed?
Need to get me a Haynes manual..........

sponger said:

Thanks
Do I need a new seal gasket upon re-assembly? (It's a bugger living 100km from the nearest parts place - and even then they'll probably have to order it in)
Does the rail just slide out once the single bolt on the bracket is removed?
Need to get me a Haynes manual..........

Click to expand...

i would suggest you get a new seal
theres 2 types
yes it pulls out
put a bit of oil or fairy liquid on it to help it back in

found a picture

Just realised I have an emmaculately clean engine (at least compared to the one in the photo!)
Having trouble getting that rail to dis-engage from the water pump.
Could it be seized in there?
Can move the whole car around and it hasn't budged even 1mm!
Should I attack it with a sledgehammer??(the rail or the car?)
Who said owning fiats was all fun and games.....

Your car is in its autumn, the icy fingers of winter beckon.

Now is the winter of my dis-content......
......although it's summer here and 28C outside....

North Island?

sponger said:

Now is the winter of my dis-content......
......although it's summer here and 28C outside....

Click to expand...

it is brass monkey's over here,
not good weather for faffin around with old punto's in

Yep North Island. Too hot to keep working for long - should have found a shadier place to park up before pulling it apart!

if you live in realy hot country
id just ditch the thermostat run it withought one. it will use slightly more fuel but will run cooler.

you wouid loose heater too but you wont need that anyway :devil:

Would be the go if the thermostat was the problem- until winter when it's -5c on those winter mornings....