General Panda 750 cooling problem...

[Vin]

As mentioned in another post, I have got the 750 back.

I don't think the running temperature is correct though, so I'm just looking for some thoughts on the matter. I will list my querys below, also when i got it I replaced the temperature sender on the cylinder head as it was knacked and also the radiator fan temp sender as that wasn't working either.

1. Years ago, when I used to run a 750 regularly the running temperature was always on 90 degrees, with the needle at '12 o clock'.

2. The current blue 750 is running at 95 or 100, the needle is on the first white marker after 90 degrees.

3. In stationary traffic the needle goes up very quickly.

4. It goes just before the red with the radiator fan kicking in and stays there. It doesn't cool down, then heat up, then cool down, then heat up and so on.

5. Once I get into free flowing traffic again it takes a good ten minutes or so to get back to the running temperature of the first white bar after 90 degrees, as mentioned above.


My thoughts are maybe that the radiator is knackered/blocked and restricting water flow, thus prolonging the cooling time....

Anybody else have any thoughts?

Vin

 

[pandafan]

Could easily be an airlock in your cooling system; if somebody other than you has put antifreeze in over the winter.

 

[Alan.D]

Where did you get the temp sendors from?

Just thinking that they may run on a slightly different ampage which could give false readings or maybe run on different heat ranges? or if you replaced the thermostat at some point it had a different heat range?

I would also check the quality/mixture of the coolant mine on a run sits just below the 90 and even in traffic very rarely goes above without the fan cutting in & keeping it there.

As for airlocks take the cap off the tank & squeeze the top & bottom hose many times to maybe force any air out.

 

[Vin]

Thanks for the pointers guys. I got the senders from Ricambio, they seemed to be identical when I swapped them over. I will check for airlocks and will probably flush it when I service it and see how that goes before doing anything else.

Thanks again.

Vin

 

[Vin]

A bit of an update on this-

I Checked for airlocks and flushed the system.

I also took the radiator off and flushed it.

This made absolutely no difference whatsoever

So I thought I'd change the thermostat, so took the one off my spare engine, and promptly broke it while I was cleaning it. So I got a new one.
Fitted it and made no difference.

Took it for a test run and found it was now going straight to 110 degrees very quickly and stopping there, unlike as it was in my 1st post. When it was at this temperature stood on the drive, I found I could put the palm of my hand flat on the radiator without any injury.

So I got my spare radiator, and put that on and found it made no difference either, straight to 110 degrees and the radiator fan coming on a few minutes after that, which isn't right.

I am now assuming that the water pump is knackered, possibly slipping on the spindle. With the water in the cylinder head getting very hot very quickly, and the water in the radiator not getting hot enough for the fan to come on, so this points to the pump not pushing the water round......just the water getting hot by convection.

I have taken the pump off my spare engine, cleaned it up and it seems OK, so I will fit this on Saturday and change the cambelt and tensioner while I am at it.

The pump appears to have no gasket, but was sealed up with an orange coloured sealant. Normally I use Red Hermetite when I do any coolant jobs, will this be OK on the pump?


Vin

 

[christopher watson]

Vin it wont be the water pump, it will be an air lock, as i am having exactly the same symptoms on my mams car. I took the water pump off and it was perfect. It looks like its a major airlock, but i wont be able to test that theory for a while as i have to dismantle the engine because a former mate of mine tried to run the engine with a loose timing belt and has knackered the engine

 

[default_user]

From what I've read I too suspect the water pump. Something else to try or maybe you already have:
Hold the inlet and outlet pipes to the radiator to see if there's a major change in temperature between them. If the outlet is 'cold' in comparison with the inlet then there may be an air lock or blockage. Because of the construction of radiators there may be blocked pipes and water will still flow through it. Depending on how many blocked pipes there are will determine how much efficiency your radiator loses.

 

[Vin]

Been away last week (Scotland, fishing) so finally got round to sorting the problem at the weekend. Replaced the water pump, and the cambelt while I was at it, and it's all back to normal now.

The old pump impeller was slipping on the shaft, you could twist it while you held the pulley wheel.

Also replaced the rotten driver's door, with the one I got from the scrappy. It was red so I got it resprayed in the proper blue by my sprayman. I swapped everything over from the rotten door into the new shell, and she's starting to look like she should

Will take some pics when it is T-cutted and polished.

Vin

 

[Pandarus]

Glad you are sorted Vin - look forward to the pics

Russ

 

[Jaff_Fox]

Someone might have already mentioned this.. I'm too lazy to read all of this, but when its up to temperature is the fan on all the time? This is a good give away to if the car considers itself as overheating as the sensor for the fan and your dash display are not the same.. alternatively is the fan kicking in at all? more times than not theres nothing wrong so long as the needle doesn't touch the red.. Watch your head gasket mate if it is overheating :/

 

[Alan.D]

You should have read it......it was the water pump & it's now sorted

Nice one VIN