Coolant leak

[Peugeot 106]

2 minutes ago, Mike Adams said:

My understanding is that it makes no difference as either allow air to escape during expansion and only liquid to return to the system. However you need the correct type of pressure cap that allows the  vacuum created while cooling to draw from the recovery tank and not the atmosphere so it needs to be sealed above the side vent pipe leading to the recovery tank.

It needs a rubber gasket on the cap as I understand it which is very thin and easily damaged. If It was thicker you couldn’t get the cap on

[Mike Adams]

5 minutes ago, Moke said:

I’m a bit late to this thread but going back to the first picture  surely there shouldn’t be a pressure cap on the engine.

The expansion/recovery tank can either be pressurised on not. Most decent vehicles dont have the expansion tank under pressure ie Toyota Landcruiser but then I am biased!

[Peugeot 106]

There is loads on the internet if you google “expansion tank versus recovery tank” but I still have difficulty getting my head round it! I think the expansion tank needs 2 pipes rather than 1 and is pressurised. The recovery tank which we all seem to have is just a pipe off the radiator neck but why you would have one rather than the others remains a mystery!

[blackrose]

4 hours ago, Peugeot 106 said:

So am I right in saying that the expansion tank is above the engine so that no vacuum is needed to suck the coolant back when it cools. With yours I assume it just drains back. Does anyone know the pros and cons of this way of doing it rather than the bottle being below the mannicooler and coolant being sucked back in when the engine cools?

 

Mine is above the engine. You can see it in my original post. I assumed it was sucked back in?

1 hour ago, Moke said:

I’m a bit late to this thread but going back to the first picture  surely there shouldn’t be a pressure cap on the engine. The pressure cap should be on the expansion tank, that way the coolant expands with heat and flows up to the tank, when the engine cools down the fluid can flow back into the engine. If you have a pressure cap between the engine and the expansion tank once the engine is switched off the pressure cap will close before all the fluid has flowed back into the engine ……at least, that’s the way it works on my car. 

 

No, the pressure cap on the engine opens and allows expanding coolant into the external expansion vessel. When it cools it's drawn back into the engine by the vacuum created. The pressure cap works either way. Or at least it used to!

Edited November 28, 2022 by blackrose

[blackrose]

Ok I've taken the thermostat housing off but the existing gasket is made from thin aluminium. Are we sure I can replace that with a 1mm paper gasket? This is the stuff I have.

[Peugeot 106]

17 minutes ago, blackrose said:

 

Mine is above the engine. You can see it in my original post. I assumed it was sucked back in?

 

No, the pressure cap on the engine opens and allows expanding coolant into the external expansion vessel. When it cools it's drawn back into the engine by the vacuum created. The pressure cap works either way. Or at least it used to!

With the tank on the floor the coolant is sucked through the cap up and in. With the tank above the engine gravity will help and you don’t need to worry about losing vacuum. But if it leaks you will lose coolant That’s my take on it but it would be great if someone (where are you Tracy and Tony?) would chip in with knowledge rather than my supposition. 

The returning coolant returns through the small valved hole in the bottom of the cap. Are sure that is OK. Try poking it open from underneath. If that is stuck nothing will get Back into the manifold. Radiator caps aren’t expensive. Make sure you get one with a rubber gasket and the same pressure rating (written on top)

good luck

[blackrose]

18 minutes ago, Peugeot 106 said:

With the tank on the floor the coolant is sucked through the cap up and in. With the tank above the engine gravity will help and you don’t need to worry about losing vacuum. But if it leaks you will lose coolant That’s my take on it but it would be great if someone (where are you Tracy and Tony?) would chip in with knowledge rather than my supposition. 

The returning coolant returns through the small valved hole in the bottom of the cap. Are sure that is OK. Try poking it open from underneath. If that is stuck nothing will get Back into the manifold. Radiator caps aren’t expensive. Make sure you get one with a rubber gasket and the same pressure rating (written on top)

good luck

 

Thanks. I'll check the hole in the cap. 

 

I wouldn't say 15 quid including VAT for a pressure cap is inexpensive, but it won't break the bank.

[Tony Brooks]

25 minutes ago, Peugeot 106 said:

With the tank on the floor the coolant is sucked through the cap up and in. With the tank above the engine gravity will help and you don’t need to worry about losing vacuum. But if it leaks you will lose coolant That’s my take on it but it would be great if someone (where are you Tracy and Tony?) would chip in with knowledge rather than my supposition. 

The returning coolant returns through the small valved hole in the bottom of the cap. Are sure that is OK. Try poking it open from underneath. If that is stuck nothing will get Back into the manifold. Radiator caps aren’t expensive. Make sure you get one with a rubber gasket and the same pressure rating (written on top)

good luck

 

Basically yes, you have it. However, although there is no signs of it in the photo my guess is, as has been said several times already, that the top of the cap is not making an air & depression tight seal onto filler neck. It needs a filler with a rubber dick under the cap. Although for canal boats pressurization is probably not vital I would be reluctant to run unpressurized if there was any chance I was going to fight a river, especially with so many boats with undersized skin tanks. If you get localized boiling on the hot spots in the head the stem will expel coolant before the temperature gauge shows a problem.

 

There are two valves in a pressure cap, the "main" spring and the larger diameter seal is the pressure valve, but a smaller one in the center that often uses part of the main seal is the vacuum valve. So a bad main seal can effect both. I am not referring to the rubber seal that I think the OP needs under the cap. I have never known the vacuum valve to clog or jamb shut, their hole may be 6mm in diameter with the valve rod passing up the middle, so to a degree semi cleaning.

[blackrose]

Just tested the thermostat in a cup of boiling water and it's not opening so that's obviously the problem..

 

Is a thick paper gasket going to do the same job as this thin metal one?

 

Edited November 28, 2022 by blackrose

[bizzard]

14 minutes ago, blackrose said:

Just tested the thermostat in a cup of boiling water and it's not opening so that's obviously the problem..

 

Is a thick paper gasket going to do the same job as this thin metal one?

 

I should think it'll be ok, easy enough job to fit a correct one if it doesn't just keep an eye on it It's very important to check the flatness of the underside of that top housing as I described earlier as they can bow betwwen the two bolt holes.

[Mike Adams]

While a paper gasket may work I would get a new thermostat,  composite gasket and pressure cap while you are doing it. For the small cost of these parts its not worth the chance of overheating the engine. That might well warp the head and/or the block on these engines.

[blackrose]

Where can I get a 82C thermostat for an Isuzu 4LE1 ?  It's got the numerals 05 stamped on it if that means anything.

[Mike Adams]

I should think enginesplus should be able to provide them all as the gasket and thermostat would be standard isuzu parts and they are the distributor.

[blackrose]

Thanks. I can't see it on their Isuzu canal engine parts list. I'm amazed something as simple as a thermostat isn't a generic part available on eBay.

Edited November 28, 2022 by blackrose

[Tony Brooks]

19 minutes ago, blackrose said:

Thanks. I can't see it on their Isuzu canal engine parts list. I'm amazed something as simple as a thermostat isn't a generic part available on eBay.

 

I think it is, have you taken the old one to a motor factors? Don't bother with the likes of Halfords because they will want to know what make and model of car.

[blackrose]

No I haven't taken it anywhere, I only took it out this afternoon. I'll take it somewhere tomorrow.

[Mike Adams]

I believe this is the correct thermostat for the engine

https://www.ebay.co.uk/itm/161514783034?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=W_-gae0XQoC&sssrc=2047675&ssuid=RODum4coRz-&widget_ver=artemis&media=COPY

[Tony Brooks]

As long as it is not a bypass stat and it has the "standard" sized mounting flange I think a BMC mini one will be the same.

1 minute ago, Mike Adams said:

I believe this is the correct thermostat for the engine

https://www.ebay.co.uk/itm/161514783034?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=W_-gae0XQoC&sssrc=2047675&ssuid=RODum4coRz-&widget_ver=artemis&media=COPY

 

I think that one is a bypass stat so the mini one would not be any good.

[blackrose]

Thanks. I'm just going to try to match it tomorrow at a car parts shop. I'm not paying 26 quid for a bleedin' thermostat, that's ridiculous.

[Mike Adams]

This is the Isuzu part number if you need it -  Isuzu 897211-2090

[Peugeot 106]

Very glad you have found the problem, and it won’t cost you a fortune. I hope all goes well

[blackrose]

30 minutes ago, Mike Adams said:

This is the Isuzu part number if you need it -  Isuzu 897211-2090

 

Thanks

7 minutes ago, Peugeot 106 said:

Very glad you have found the problem, and it won’t cost you a fortune. I hope all goes well

 

Thanks to you too

[blackrose]

I visited 3 auto parts places today including for 2 truck parts but none of them could supply an equivalent thermostat. 

 

So it looks like I'm forced to pay £26 +vat and postage for a simple thermostat unless anyone knows a good auto parts cross referencing website?

[blackrose]

15 hours ago, Mike Adams said:

I believe this is the correct thermostat for the engine

https://www.ebay.co.uk/itm/161514783034?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=W_-gae0XQoC&sssrc=2047675&ssuid=RODum4coRz-&widget_ver=artemis&media=COPY

 

I just called the seller who said it's not for the Isuzu 4LE1 (my engine).

Engine Plus have just quoted me £92.45 including postage and vat 😵

 

I never thought it would be such a struggle to obtain a simple engine part...

 

Where do others get their parts from?

[blackrose]

I've ordered a couple of these from ASAP Supplies. They give all the dimensions on their website and it seems to match mine. Works out at 20 quid each including postage and vat.

 

Edited November 29, 2022 by blackrose