New Member in Guernsey UK

[Fredjohn]

An out of the box thought. Has a previous owner wrongly wired the electric water pump to run whilst the engine is running?

The electric pump operates in the opposite direction and should only come on once the engine is off and temp is high.

[dapinky]

Wevster,

As a new water pump can be got quite quickly anyway, but is a bit of a pain in the bum to get to and change, it may be worth getting to the stage where you can remove the current unit for examination before committing to buy another, if it is not working, it should be pretty obvious. There isn't much inside to go wrong, so it will either be intact and correct, or not.

As Ken says, if the heater is getting hot, then it should be that the pump is pushing water to it, but my thought is that the heater take-off is at the top of the engine, and before the thermostat, so it would get hot water to it from the thermo-syphon effect - but would also work if the thermostat is not opening.......

...... unfortunately, this is one of those puzzles that *could* be a few different things, with the same symptoms - some are easy to address (airlocks) some not so easy, but still straightforward (thermostat, hoses, radiator blockage etc), and some are a PITA (waterpump).

[Hector2021]

How about if you remove the thermostat but replace the housing and then run the engine with the top hose disconnected (or loose enough to allow leakage) Obviously dont run it until it gets hot, but it should show if the main pump is forcing coolant through the engine?
The flow rate might suggest between a duff pump and a good pump depending on how well it outputs coolant.

[Tuga2112]

How about if you remove the thermostat but replace the housing and then run the engine with the top hose disconnected (or loose enough to allow leakage) Obviously dont run it until it gets hot, but it should show if the main pump is forcing coolant through the engine?
The flow rate might suggest between a duff pump and a good pump depending on how well it outputs coolant.

you can use the inertia switch to stop the engine from firing and just use the starter

under normal circunstances its not a good idea because the starter is not meant to operate for very long. but i am pretty sure about 20 seconds wont cause any ddamage... i have had the Saab starter go thorugh a lot more hell than that and its still going strong. I would hope thats enough to notice some flow ?

[dapinky]

Personally, I'd prefer to go with Hectors suggestion, as the water pump would rely on spinning at quite a speed to get the water flow going..... not sure of the benefit to loosening a hose (other than to get a leak before pressure builds up), but maybe just leave the cap off the header tank.

It has got to be worth trying whatever you can before getting into a pump replacement scenario.

[Wevster]

Hi thanks
I’ve ordered a new pump from PNM and had a chat with the mechanic there, he has had a similar issue where he repaired a head gasket failure and on inspection of the water pump which looked good from the outside found that the impeller had come loose and was still spinning at idle but obviously not working under load. So although a tricky and time consuming job that’s my next port of call. I’ll report back my findings and let you know what I find, a least I can eliminate that area. Wish me luck.

[Tuga2112]

im pretty sure ive done a video on the timing belt (including water pump) replacement.

i think Toby also covered that topic. your likely to have 2 different approaches on the subject on youtube on top of all the information on here (dont forget to check the wiki)

[Wevster]

Failed pump

IMG_2159 2 Small.jpeg (21.48 KiB) Viewed 8382 times

Problem solved, when I removed the water pump the impeller fell off its spindle. It all looked good from the outside with no leaks, but unfortunately it didn’t last long or do much mileage as it was fitted October 2023, and as yet not covered a 1000 miles. No sure if it’s a recognised make.

[Tuga2112]

now its very important to know what brand is that. so we all can stay clear of it

[dapinky]

Well, I'm sort-of pleased that my 'distant diagnoses' proved correct, but it isn't a good thing at all.

Clearly a faulty part, and I can only hope that it hasn't come from a 'faulty batch'.

Please can you let us know where and when it was bought, and which make it is (if known) as many of us will have spare units like this on the shelf ready-to-use and may benefit from that information.

Do you already have a new one to fit, or if not, I am happy to send you one to get on with, to be replaced whenever is convenient?

[Wevster]

Thanks for the offer that’s very kind, I’m waiting for a new unit to arrive from PNM. I know the garage that fitted the old pump so I’ll give them a call to see if they can remember where it was from. Anyone know what this random red wire hanging down under the turbo right side of the engine bay, I can’t see anything obvious.

[Tuga2112]

i cant see because the picture is too small. but my guess given the location is that its the one that connects at the bottom of the power steering pump.

[dapinky]

i cant see because the picture is too small. but my guess given the location is that its the one that connects at the bottom of the power steering pump.

According to the wiring diagram, the wire for the PAS pressure switch should be black with a blue trace....... but it is in the right sort of location, so worth checking if there is a wire on the connector right at the bottom of the PAS pump

[KenS]

My S2 has two cables in that lower corner, one goes to the bottom of the power steering pump, the other is 'not connected', I assume its for air conditioning?

Interested in the water pump, the logo on the casting is for US Motor Works, looks like they can be sourced from Rock Auto and UK Lotus parts centers and ebay, part number US9221

[Wevster]

Hi All
I've spoken to the garage that did the job originally, and they bought most of the parts from Classic Team Lotus in August 23. So, I gave them a ring and spoke to their parts dept and they informed me that they haven't had any issues before regarding this pump. I was told that they are sourced from a UK supplier but I don't know where they are made. Hopefully its a one off defect and not a batch defect. I'll have a look at the new pump when it arrives (hopefully today) and then fingers crossed, just got to fit it!

[Tuga2112]

Hi All
I've spoken to the garage that did the job originally, and they bought most of the parts from Classic Team Lotus in August 23. So, I gave them a ring and spoke to their parts dept and they informed me that they haven't had any issues before regarding this pump. I was told that they are sourced from a UK supplier but I don't know where they are made. Hopefully its a one off defect and not a batch defect. I'll have a look at the new pump when it arrives (hopefully today) and then fingers crossed, just got to fit it!

probably the usual UK network of specialist that effectively works with Miles Wilkins.

is there any markings in the old pump you can send us ?

they could be made to spec but they are most likely isuzu stock re-branded and we know from rockauto theres usually a few different options avaibalae.

[KenS]

The logo is shown on the original photos of the failed pump, it is a 'US Motor Works' pump which seems quite common as a non-OEM pump, being supplied at times by RockAuto, UK Lotus parts centers, ebay. The manuf. part number is US9221

[dapinky]

US Motorworks is a recognised aftermarket supplier across the industry - it wouldn't be my first choice of 'make', but, that said, the options are getting fewer all the time, and I've not heard bad things about them, but have always preferred to get Gates, Beck/Arnley, or similar whenever possible.

Lets be honest, if they were believed to be crap, Classic Team Lotus wouldn't be supplying them!