Technical Huge overheating/water pump gone???

[f1ian]

Hi All.


I'm hoping the collective knowledge here may be able to help me.


This morning on a drive all was OK with my Seicento Sporting. This afternoon - not so much!


The high temp light came on, pulling over and popping the bonnet I was met with a violently bubbling expansion tank, steam pouring out everywhere etc.


I let it cool down, looked inside the tank - empty - stole some water for the drive home (another boil over and wait on the way) and had a look


No obvious sign of water on the dipstick / oil filler hole / exhaust pipe tip / no oil in the radiator expansion tank, squeezing the top hose made gurgling sounds and signs of movement in the tank. The engine runs fine - no mis-fires or lack of power etc. There are no horrible sounds coming from anywhere and alternator is charging fine and its belt is still on.


After a full cool down to cold, top up to max and test drive it boiled after approx. 2kms. Waiting for a cool down and complete the journey had emptied the tank again. (engine still running fine apart from the obvious...)


I'm thinking that it must be the water pump that's given up but maybe someone can advise - I have mainly air-cooled cars in the past and never actually changed a water pump - what exactly fails??? I have no water loss from underneath as far as I can see, the amount of water loss must be from boiling/spraying it everywhere - no way it could still run normally if it was a head gasket


One thing - revving the engine shows no water movement in the tank (hot engine) I would have expected so see bubbles or something.


I would appreciate any advice to get me back on the road - I'm thinking of ordering a pump and thermostat housing to be safe - Its going to be a bit tricky job given that currently I can't pop out to get bits with the lockdown and all so any advice of what to get as an order would be very greatly received.


Many thanks
Ian

 

[David C]

Does the ran fan work?
I think on the MPI it is switched by the ECU probably via a relay, but on the SPI it is by a thermal switch on the rad.

 

[f1ian]

Hi.


The rad fan has cut in although with less water in the system i'm not surprised if it's normal operation is a bit shakey - if the temp switch is not in contact with water then it probably will not work as normal!


Ian

 

[David C]

The rad fan has cut in although with less water in the system i'm not surprised if it's normal operation is a bit shakey - if the temp switch is not in contact with water then it probably will not work as normal!

Depends which way round the issue is happening.
If the fan wasn't running, that will cause it to overheat and boil over.

With that the rad would be scalding hot when it boils over.


But if the issue is the pump failing the rad will likely be less hot (potentially cold) when the coolant boils over.


A lot harder to diagnose on a Sei with no temperature gauge.

 

[f1ian]

Mmm. Yes, not a great plan by Fiat to give up on the need for a temp gauge! I was waiting for the forums wisdom before trying anything but I will try another start then feel across the radiator to see if it is hot.


I have been doing a bit more reading and another trick is to take off the top hose and start the engine - if the pump is pumping water should come gushing out. Of course a closed thermostat could make a problem with that test so maybe popping off the housing before that test could be the trick.


Thanks for the suggestion!


Ian

 

[rallycinq]

Have you bled the system each refill?

D

 

[purf]

Thermostat stuck closed in position is a posibility.

 

[David C]

Thermostat stuck closed in position is a posibility.

It’s possible, but when they fail they usually stick open and run cold.

 

[f1ian]

Hi.


So further running shows a pretty cold radiator and a boil in the expansion tank within a mile or so. I have just received a new water pump from ECP with cambelt & tensioner so I think this will be the next step since the engine still runs fine apart from the impressive boil


I have opened the bleeds (behind O/S headlamp & bulkhead by wipers) and water dribbles out - no squirt under pressure that I was hoping to see so the more I look the more I am convincing myself that its water pump.


Time to find out how clever I am (or not...)


Thanks
Ian

 

[varesecrazy]

On the bright side.. you get to check the OSF brakes and suspension

Hope it sorts it for you

 

[dante giacosa]

this sounds very odd

I suppose changing the water pump in the first instance will reveal a lot. Not least of which about the pump itself? Do they ever actually 'seize'?

What's the mileage on your example, Ian..?

I fitted a coolant gauge on mine, back in the day; I think I used a blanking plug on the OS block for the sensor, and ran an Alfa 156 gauge. (sorry that doesn't help you, obviously)

 

[purf]

It’s possible, but when they fail they usually stick open and run cold.

They usually do but i only mention it as it happened to my old cinq. Managed about 2 miles in the summer before steam everywhere.

Easy enough to check by removing the inner stat and inspecting.

Either that or the head gaskets leaking...

 

[f1ian]

Hi All.


Thanks for the comments and advice. To answer one of the questions the car has 91K on it.


My pump and cambelt have arrived (Euro Car Parts are taking a week or so but deliveries are getting through)


I was put off by rain but the other day I had another look since i'm a bit nervous about taking it all apart when getting parts is a bit long-winded


Something interesting happened - I let it run with the expansion tank cap off. It ran fine, water did come out of the bleed points when revving the engine but after about 10 mins of idling the water in the expansion tanks was starting to steam and hot to touch. Then the fan cut in. Within about 10 seconds it was a fountain out of the tank!!
After shutting it down I felt the top and bottom hoses and the bottom of the radiator. Top hose warm, rad and bottom hose cold.


I think Purf's (and others) suggestion of the thermostat maybe worth a go before stripping the pump out. I bought a new thermostat but can even chop up the old housing to remove the thermostat unit itself to see if it has seized shut.
I'm wondering if it was running OK until the point when the thermostat should have opened - if it didn't - that's when it boiled out of the tank


Thanks for the advice everyone! Its a friendly forum here and the Cinq/Sei section is always active.

 

[dante giacosa]

I wonder if you've got a blockage

I wonder if the radiator has gummed up, somehow...

 

[f1ian]

Hi Everyone.

Cautiously I think this may be fixed -

I started the job with the thermostat - new one ready to be fitted but getting the old one out was a pig - very tight screws and it really didn't want to come off. The condition of the screws was very poor, all of the hose clips were crimp not worm drive and the housing had FIAT on it. I am wondering it was original? - who would fit genuine parts onto an aging cheap car? I was getting very suspicious of the 'stat.

I cut out the thermostat mechanism to have a look and it was pretty stuck in there. Refitting the old- empty- housing and refilling I test started the engine.


No sign of overheating, the fan cuts in and out, the top hose is hot, the bottom hose is warm to hot (cold before) and the bottom of the radiator is warm to hot (cold before). Bleeding out went fine.
OK, my heater is now cool but I plan to run it for a few days, if all seems OK then swap to the new stat. and add coolant. Getting back to a correctly operating system should bring back my heater as I expect the lack of thermostat allows water to bypass the heater matrix.

I think that's it - I will swap the pump when its a good time just because I have it a new cambelt cant be a bad thing but if it runs fine again like this then I don't want extra work at this time. I am looking at threads where to fit a temp gauge and the location on the block that was mentioned earlier.

Sorry if I have gone on a bit but hopefully if someone else has similar symptoms they can follow the steps and advice. Thanks everyone!!

Ian

 

[David C]

I started the job with the thermostat - new one ready to be fitted but getting the old one out was a pig - very tight screws and it really didn't want to come off. The condition of the screws was very poor, all of the hose clips were crimp not worm drive and the housing had FIAT on it. I am wondering it was original? - who would fit genuine parts onto an ageing cheap car? I was getting very suspicious of the 'stat.

Crimp single-use hose clamps is a sure sign it hasn't been off before.
I don't think anyone would refit those.

 

[f1ian]

It’s really quite impressive for a £600 eBay special with 91k on the clock and signs of having led a fairly colourful life to have got that far on what really appears to be mostly original bits. When one of the coil packs gave up it was the same. I ended up with the Seicento accidentally when I needed a temporary fill in car for a couple of months- that was 5 years ago and it’s been a catastrophe in some areas- clutch cables and linkages mainly, an intermittent battery drain and electrical faults that showed how little the loom seems to resemble the diagram but in other areas it’s been outstanding.
It gets laughed at and my partner and I have an agreement that if it breaks down when she is in it then she will not be asked to push but it always makes me smile when it works!!