Coolant filler cap compatibility 100 vs 140

[robwijnstok]

Good evening all,

Like other members on the forum my 75 is loosing some small amounts of coolant. I have checked the forum, and the filler cap is one of the probable causes. Indeed I could smell a bit of coolant near the filler cap, so I ordered a new one at the Rover dealer, part number is PCD000080. I have looked also on other suspected places also, but no signs of coolant.

Today I received the new filler cap, but when I would replace the old one with the new one I saw on the underside of the old cap a brownish colored circle with 140 stamped on it.

The new filler cap is black on the underside, and there is 100 stamped on it. On the picture you can see the new one.

My question is, are these caps the same? I think the 100 and 140 could be the temperature or pressure when the filler cap opens so damage to the cooling system can be prevented? Who knows what the 100 and 140 mean?

Rob.

[stevemac]

Originally Posted by robwijnstok

Good evening all,

Like other members on the forum my 75 is loosing some small amounts of coolant. I have checked the forum, and the filler cap is one of the probable causes. Indeed I could smell a bit of coolant near the filler cap, so I ordered a new one at the Rover dealer, part number is PCD000080. I have looked also on other suspected places also, but no signs of coolant.

Today I received the new filler cap, but when I would replace the old one with the new one I saw on the underside of the old cap a brownish colored circle with 140 stamped on it.

The new filler cap is black on the underside, and there is 100 stamped on it. On the picture you can see the new one.

My question is, are these caps the same? I think the 100 and 140 could be the temperature or pressure when the filler cap opens so damage to the cooling system can be prevented? Who knows what the 100 and 140 mean?

Rob.

It can't be temp. You wouldn't want it opening up at 100, as I understand it normal operating temp can be over 100deg.

[TrevorL]

I am sure the 100 stands for 1bar, 140 stands for 1.4 bar pressure as the BMW 2 bar cap is marked as 200, the caps are of BMW design made by Reutter, the last one I purchased 2006 was 140 1.4bar MG Rover marked as 1 x ESR 1480

http://www.the75andztclub.co.uk/foru...685#post238685

Trevor

[JohnDotCom]

The Part Number you quoted is for 1.8 and V6 2.0 Litre up to serial No: 158719 only
after that chassis Number use Part No: ESR1480 Cap-expansion tank pressure £9.99 + VAT.

[kaiser]

You are seeing the release pressure, so one opens at 100kPa and the other at 140. Higher values, higher temperature before boiling.
You are indeed right, the cap could let it out, and it is difficult to spot, because there is no overflow pipe, so it just runs out around the cap, and gets blown/dried away. Difficult to spot.
However you must make sure that you are not loosing the water at the other known spots. Pump, thermostat, plastic pipes.
Internal losses, watch out for mayo under the oil filler cap.
As for the water loss, check under the sound plate in the V to see if there is water there. Check the belly pan on the right hand side for trace of drip from the water pump, which will often run down past the belt tensioner. Remove the RH front wheel to get a good look.
You must also make sure that you don't overfill the expansion box, as that will be blown out, even if the cap is sound. Fill only to MAX mark on side of box. It is lower than you would guess.
And above all, always keep an eye on the water in these engines!!!

[T-Cut]

What would be the effect of using the diesel (1.4kPa) cap on a petrol engine (100kPa) apart from the tendency to run hotter?

The OP's V6 appears to have been using a diesel cap.

TC

[kaiser]

It would not necessarily run any hotter, but would be able to sustain higher temperatures in the system before spitting fluid out.
I think an advantage is to use the higher pressure units, so long the pressure does not reach levels that could damage other items, like radiators, pipes or expansion boxes.
I run one marked 200, so obviously that is off a BMW somewhere along the line.

[robwijnstok]

Originally Posted by JohnDotCom

The Part Number you quoted is for 1.8 and V6 2.0 Litre up to serial No: 158719 only
after that chassis Number use Part No: ESR1480 Cap-expansion tank pressure £9.99 + VAT.

Evening JDC,

Today I phoned the dealer to check and ask what they think the numbers mean, and if they have send me the right one…
I was told that for the 2,5 liter KV6, PCD000080 should be used. But they have send me a “100” version, and not a “140” version what is the old one in my 75.
My vin number is 278252, so I should be using a “140” cap, right?

Can you check, or do you know if the pressure is matched/belongs to the part number?
PCD000080 what was send to me is the “100” type, and only for the 1,8 and 2,0 liter V6 up to vin 158719, as you wrote in your replay.
ESR1480 is the “140” type cap, as you mentioned in your replay, for the 2,5 liter, and 1,8 and 2.0 liter from vin 158720.

Is the ESR1480 a Rover branded cap?
My dealer told me that the only 2,5 liter V6 expansion pressure cap what can be ordered via X-Parts is the PCD000080.

Rob.

[JohnDotCom]

Is the ESR1480 a Rover branded cap?
My dealer told me that the only 2,5 liter V6 expansion pressure cap what can be ordered via X-Parts is the PCD000080.

that is incorrect it is shown as can be seen below & in PDF.
The EPC that is XPart's Electronic Parts catalogue Oct. 2008 shows the Part numbers I have attached PDF for you to show dealer.

Incidentally the Cap ESR1480 is the same one for the Diesel and is 140.

From Year Prefix YM from 158719 VIN for P/No: ESR1480 Expansion Tank-V6 Petrol 1.8 Turbo and 2.0 Diesel Price: £9.99 + VAT
From Year Prefix YM to 158718 VIN for P/No: PCD000080 Expansion Tank-V6 Petrol and 1.8 Price: £10.39 + VAT

[robwijnstok]

Originally Posted by kaiser

You are seeing the release pressure, so one opens at 100kPa and the other at 140. Higher values, higher temperature before boiling.
You are indeed right, the cap could let it out, and it is difficult to spot, because there is no overflow pipe, so it just runs out around the cap, and gets blown/dried away. Difficult to spot.
However you must make sure that you are not loosing the water at the other known spots. Pump, thermostat, plastic pipes.
Internal losses, watch out for mayo under the oil filler cap.
As for the water loss, check under the sound plate in the V to see if there is water there. Check the belly pan on the right hand side for trace of drip from the water pump, which will often run down past the belt tensioner. Remove the RH front wheel to get a good look.
You must also make sure that you don't overfill the expansion box, as that will be blown out, even if the cap is sound. Fill only to MAX mark on side of box. It is lower than you would guess.
And above all, always keep an eye on the water in these engines!!!

Hi Kaiser,

Thanks for you replay.

I have looked and sniffed around my engine as a young dog looking for a place to P, this must have been fun for my neighbors to see. Everything is dry and the oil filler cap is clean and without mayo. Only thing I can see is a pink edge on the outside rubber from the filler cap. This must be the "leakage" spot. Also the rubber of the new one is complete flat and the old one is not flat anymore. Near the filler cap is the only place where I can smell the coolant.

Rob.