Isuzu Trooper Owners Club UK™

wilbyhilbly · ** Joined: 24 Dec 2013 Posts: 74 Location: North Yorks

About a month ago the truck overheated, I had had it since November and must admit I never checked the rad after the new one was fitted so I assumed maybe the coolant level eventually went down.

I filled it up and it has been fine since, however, this week the temp gauge started going up slowly then coming down again and eventually the check engine light came on and it had overheated.

I checked all the usual, no water in oil, no water coming out the exhaust etc. refilled it, and it's fine again.

The only thing I do not understand is, the level of the expansion tank has stayed at exactly the same level both times, should it not go up and down according to the rad level?

Sounds a bit pathetic I know, but I am a newbie as far as Isuzu is concerned, loving it though!.

John

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Browndoff · Posted: Sun Apr 27, 2014 23:14 Post subject:

The coolant system depends on good air-tight seals on the rad-cap, on the expansion-bottle and on the plumbing being leak-proof.

As the engine heats up, the water should expand into the bottle - so the level should be higher when the engine is hot. When it cools down, the air-pressure in the bottle [open to normal atmospheric air-pressure] forces the water up the tube and back into the radiator - so the level in the bottle should be LOWER when the engine is cold.

If you have a ragged seal on the rad-cap, it will let air in THERE - so the water won't come back from the bottle. If the water-tube END is not below the level of the water in the bottle, then the air will go straight in through THERE - and, again, the water will not return from the expansion-bottle. If allowed to continue, the radiator's water-level will drop and engine-cooling will deteriorate dangerously. It's a very simple system - but it MUST be made to work properly!
_________________
2002 LWB Trooper 3.0L
I've done some major repairs, including replacing half-shaft, replacing fuel-injectors etc.

darren m · Posted: Mon Apr 28, 2014 15:22 Post subject:

browndoff -- few days ago i was just checking my header tank and noticed it was empty , so i undid the rad cap and was amazed at how much pressure was in there pushing the cap up , although the engine had been run it had been at rest for about an hour -- is that normal

i,ve topped up the header which as dropped a bit but seems stable in its level

does that sound like its working ok , is there supposed to be that much pressue

thank you
_________________
93 SWB 3.1Turbo Duty intercooler

99 LWB 3.0 TD Citation

2000 LWB 3.0 / 3.1TD Duty conversion

Browndoff · Posted: Mon Apr 28, 2014 19:25 Post subject:

ALL water-based coolant-systems in Internal Combustion Engines become pressurized, to some extent. THAT'S why they have a spring-loaded rad-cap - it's to act as a pressure-release-valve - i.e. if the pressure exceeds the 'intended' level, the pressure will lift the internal cap and allow the coolant to overflow into the reserve-bottle. It's also why they ALWAYS have a warning-lable to tell people NOT to undo the cap while the engine is still hot!

You've got to check the level - and MARK the outside with a permanent marker felt-pen - both when the engine is cold and again when it's hot. The bottle should fill up when it's hot and go back to about half-full when the engine is cold. If it's NOT moving, then there's an air-leak into the system and your coolant-system is NOT working properly.
_________________
2002 LWB Trooper 3.0L
I've done some major repairs, including replacing half-shaft, replacing fuel-injectors etc.

darren m · Posted: Mon Apr 28, 2014 23:27 Post subject:

thank you - I will double check that
_________________
93 SWB 3.1Turbo Duty intercooler

99 LWB 3.0 TD Citation

2000 LWB 3.0 / 3.1TD Duty conversion

wilbyhilbly · ** Joined: 24 Dec 2013 Posts: 74 Location: North Yorks

Well I finally found the reason my level was static, the tube inside the expansion bottle was blocked solid with a load of brownish/pinkish sludge.

I cleared that and it worked fine for a while but then got a little sludge in again.

It seems that there is quite a bit of this stuff in the bottom of the bottle, so I think it is being drawn up the tube when it cools off.

Is there a simple way to get the expansion tank off to clean it out, or any other suggestions.

Thanks in advance.

Browndoff · Posted: Tue May 27, 2014 18:08 Post subject:

Nothing could be simpler! At least, in my 4JX1, the Expansion-Bottle has a simple wedge-shape moulded into its face [grill-side], which drops into a steel-bracket attached to the front metalwork. Just remove the cap and tubes and it'll lift out easily.

If you can't get your hands in to clean it properly, half-fill it with sand and water and shake it like James Bond's cocktails! It must be spotless when you return it to service - so you can see the level through the sides!

If the gunk RETURNS after cleaning it - then you may have OIL getting into your coolant channels - which is another problem entirely!
_________________
2002 LWB Trooper 3.0L
I've done some major repairs, including replacing half-shaft, replacing fuel-injectors etc.

wilbyhilbly · ** Joined: 24 Dec 2013 Posts: 74 Location: North Yorks

Great stuff B thanks very much. Again!!!!

What would I do without you Smile

darren m · Posted: Mon Jun 09, 2014 16:13 Post subject:

if the water in the header tank is hot ie. you pop the lid off while running and you can feel the heat rising -- does that mean its working ok

i,m just wondering as i also noticed the header level never seems to move between hot or cold engine , but the water in there does get hot.

all pipes got hot and check rad when cool and it was full

thanks
_________________
93 SWB 3.1Turbo Duty intercooler

99 LWB 3.0 TD Citation

2000 LWB 3.0 / 3.1TD Duty conversion

Browndoff · Posted: Mon Jun 09, 2014 20:34 Post subject:

I suppose that if it's getting HOT in the bottle - then there MUST be some flow of hot water into it - and unless it gets higher ever time the engine runs, it must flow back out again when it cools.

I think that's what I said SHOULD happen!
_________________
2002 LWB Trooper 3.0L
I've done some major repairs, including replacing half-shaft, replacing fuel-injectors etc.

darren m · Posted: Mon Jun 09, 2014 22:19 Post subject:

thanks BD - so it must be ok.
there is only one pipe isnt there , the top one coming from the rad , is that correct

cheers
_________________
93 SWB 3.1Turbo Duty intercooler

99 LWB 3.0 TD Citation

2000 LWB 3.0 / 3.1TD Duty conversion

darren m · Posted: Fri Jun 13, 2014 17:30 Post subject:

after a bit more testing Rolling Eyes

, the header tank is not moving and not getting hot .
i thought it was but i know think that the heat was just coming from the rad and passing through the bottle , it was just and i mean just luke warm after a drive.

so when cool , i,ll take rad cap off should it be full to the top
_________________
93 SWB 3.1Turbo Duty intercooler

99 LWB 3.0 TD Citation

2000 LWB 3.0 / 3.1TD Duty conversion

Browndoff · Posted: Fri Jun 13, 2014 18:12 Post subject:

YES - hot or cold - the Rad should be full to the brim! That's why you have a separate tank to allow for the expansion of the water as it heats up - so the 'important' tank [the Radiator] stays FULL!

The usual reason why it might be less than full, is simply that the Rad-Cap-Seal has become 'tired' and is letting in AIR. When the seals are good and the tubes are clean, the coolant-water should flow from Rad to Tank and back again, as it expands when HOT and contracts when COOL.
_________________
2002 LWB Trooper 3.0L
I've done some major repairs, including replacing half-shaft, replacing fuel-injectors etc.

darren m · Posted: Sat Jun 14, 2014 10:02 Post subject:

thanks BD - a new rad cap and clean out the long tank pipe to do today

are the rad caps a certain type or will any motor factor one do

thanks yet again
_________________
93 SWB 3.1Turbo Duty intercooler

99 LWB 3.0 TD Citation

2000 LWB 3.0 / 3.1TD Duty conversion