Technical Overheating problem

[rusty]

yes

Which bit is the YES to ?

 

[arc]

Which bit is the YES to ?

Is the coolant temperature sensor a different part to a radiator fan switch?

that bit ^^

there are 3 sensors associated with coolant on the SPI Sei.

One is in the back of the cylinder head, timing end. It is the one that controls the gauge / overheat light. This is all it does. Costs around £10

The second is in the inlet manifold. The inlet manifold has a waterway in it. The sensor is in that waterway. This sesnor is used by the ECU so that it knows the coolant temperature (important!). These cost a lot, £41 by the sounds of it.

The third is in the radiator. It is on the right hand side of the rad, in the middle. It is a thermostatically controlled switch. Once the rad reaches 92c, it switches. This switches the fan on. Once the temperature falls to 87c, it turns off again. This is all it does. They cost around £10 too.

 

[rusty]

Since I have not herd the fan in a long time I would assume that I need a new radiator fan switch? and whilst we are on the subject is there anyway of fitting a coolant temperature gauge easily?

Thanks arc you are the font of all knowledge.

 

[arc]

Thanks arc you are the font of all knowledge.

thanks

You say it overheated after just coming off a dual carriageway. Did it overheat in traffic, just after it?

There are quite a few aftermarket temperature gauges around. They're pretty easy to fit as well. Ebay, or demon-tweaks are a good place to start. (you want an electrical gauge, not mechanical!)

You may as well swap the raditator fan switch. It's an expensive part, and if it sorts the problem

A new switch is indeed S4P262 on shop4parts. It won't be much more at a fiat dealership though, and you wont have to pay delivery.

 

[rusty]

I have now ordered a new fan switch at £8.51 and a new cap at £3.46 both plus vat from my local Fiat dealer.

 

[rusty]

You say it overheated after just coming off a dual carriageway. Did it overheat in traffic, just after it?

It was at 6 in the morning no traffic. i had probably been doing 70ish for 10 miles and had gone down to 40ish for 1 mile before the temp light came on.

 

[arc]

To me, that doesn't sound like a problem with the fan - at 40, there should be plenty of airflow to cool the rad. I'm swaying toward expansion cap still. But you may as well replace them both. Make sure you fill it with the correct antifreeze mix, and bleed the system properly. Bleed screws are behind the drivers side headlight (tube that comes up from the inner wing) and the second is just to the right of the battery were the pipe goes through the firewall to the heater matrix.

 

[rusty]

What is the ratio of the anti-freeze mix? and what is the coolant capacity of the cooling system?

 

[arc]

cooling system is 4litres. the mix depends on the antifreeze, the stuff i use (halfords stuff) is 1 part antifreeze to 2 parts water

 

[rusty]

Okay, today I have collected a new coolant tank cap and radiator fan switch from the dealer. I have drained the system, fitted the new switch, flushed the system, refilled it with a water/anti-freeze mix and bled the system. The hour-ish that I had the car running on tick over for flushing etc. the fan only kicked in once (which I was glad to hear once it did). once it was all finished I checked for leaks which there were none and took it for a 20 mile drive. only my return I had found that it had used all the coolant in the expansion tank. looked underneath and the coolant was coming out at a good rate. had a look around the engine bay and it seems to be coming out under pressure from behind the timing belt cover.
What could be leaking/blown behind there?

 

[midland fiat]

core plug or water pump!

 

[rusty]

Which part of the water pump normally goes? The gasket or the seal around the shaft?

 

[midland fiat]

They go every way! No one bothers to change when doing belts etc.

Either way change the pump, if it is that, dont bother trying to reseal yours.

 

[rusty]

How much is the pump is from Fiat? Anybody have a photo of the behind the timing cover/water pump in in place?

 

[midland fiat]

i get them at a good discount, i think 16 pounds retail (unsure exactly), use a motor factors, more likely to be in stock!!!!!

 

[rusty]

Im assuming the timing belt will need to be removed to replace the water pump? How is everything locked into place?

 

[midland fiat]

Best to take the cambelt cover off and determine if it is the pump or core plug or something else before thinking on replacement particulars!

 

[rusty]

I have taken the Fiat to bits this morning and the seal around the water pump shaft has gone.

You can see that coolant coning off the top of the pulley.
Can somebody guide me through the best practise of changing the water pump and the best place to get one?
Oh i have just had the timing belt changed by Fiat, It seems a bit loose. What are the measurement deflections on this? And is the adjuster automatic?

 

[arc]

that is a funky picture

Removing the water pump is easy. Couple of bolts / nuts hold it onto the block. I think there are four in total. Picture shows roughly where 3 of them are.

You will need some sillicone based gasket sealing stuff, when you get the new pump you will see a small lip round the edges of it. Put a thin bead of sealant into this. Then stick the pump on, and tighten the bolts down to 8nm and the nuts to 10nm.

Timing belt does not auto adjust the tension. That is handled by the tensioner. To set the tension, you need to loose then nut holding it in place and then twist it - you'll see what i mean when you are working on it.

Correct tension, you should be able to just twist the belt 90degrees when held between finger and thumb on the belts longest run.

Motor factors should have a new pump.

 

[rusty]

Is there no gasket or rubber seal?

since you are up on Fiat prices arc, what is the price of a water pump from them?