Overheating Again

Well, after all the work I put into this car, the problem has again reared its ugly head. Got about ten miles and climbing a steep, long drag the temp almost got into the red. Admittedly we were towing our 20 odd foot caravan and as usual loaded to the gunwalls but I would have expected it to have managed that.
Not long ago fitted a new radiator, water pump, stat, expansion tank cap, belts and tensioner. What else can it be??? No emulsification in the oil, no muck & no bubbles in the expansion tank. Maybe an air lock but how do you get rid of that?

Hi sorry to hear you are having trouble. Did you check the stat in a pan of water with a thermometer? The first one I bought opened at 98C so changed that for a genuine one which opened by about 88c, The radiator should self bleed. Take off your expansion cap and squeeze you rad hoses and see if water or air comes out of the small bleed off pipe which comes off the top of the rad to the expansion tank. Are your hoses ok? Are they bulging. Is your viscous fan ok? Does it roar when hot?

Does it overheat with the caravan but the PSI Box removed?

dean68uk said:

Does it overheat with the caravan but the PSI Box removed?

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Hi Dean,

I didn't check the stat when I put it in as it was new and I thought it should be okay, I will check it though. I don't think it roars when hot and I don't think the hoses are bulging. I haven't tried it with the PSI box disconnected when towing the caravan but I have just finished fitting the switch so I can switch it out of circuit (I am considering just disconnecting it altogether) I am going to our local indy tomorrow to get a sniff test done so I can be sure there is nothing drastic in there. The oil is clean and there seems to be no contamination of the water. Tick over is spot on and starting is 'on the button, every time. I might try the hot water test first though.

Did you fit an electric fan?

enery8 said:

Well, after all the work I put into this car, the problem has again reared its ugly head. Got about ten miles and climbing a steep, long drag the temp almost got into the red. Admittedly we were towing our 20 odd foot caravan and as usual loaded to the gunwalls but I would have expected it to have managed that.
Not long ago fitted a new radiator, water pump, stat, expansion tank cap, belts and tensioner. What else can it be??? No emulsification in the oil, no muck & no bubbles in the expansion tank. Maybe an air lock but how do you get rid of that?

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I'd check the stat or try without it and also check the viscous fan unless you have done the electric conversion.
Otherwise it could be a cracked head especially as it has a history of overheating.

pm Datatec,he has a cheap fix using the a/c fans to assist cooling.This will not sort out your underlying fault though.Check stat as stated,get sniff test,when you changed rad did you check the interior of the hoses?Depending on the construction of the hose it is possible for the interior to close under suction of the water pump and the exterior to look normal.It doesnt happen very often but it is possible.Cannot remember if you posted that you checked the fan coupling.

dean68uk said:

Did you fit an electric fan?

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Yes, It has manual override and I switched it in when it started to get over warm but that did not seem to make any difference. I then re-set the controller to continuous and it still overheated on this one long drag of a hill.

enery8 said:

Yes, It has manual override and I switched it in when it started to get over warm but that did not seem to make any difference. I then re-set the controller to continuous and it still overheated on this one long drag of a hill.

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So check the stat and if that's good I reckon you are looking at a cracked head. The problem often only shows when then engine is working very hard.

tomcat59alan said:

pm Datatec,he has a cheap fix using the a/c fans to assist cooling.This will not sort out your underlying fault though.Check stat as stated,get sniff test,when you changed rad did you check the interior of the hoses?Depending on the construction of the hose it is possible for the interior to close under suction of the water pump and the exterior to look normal.It doesnt happen very often but it is possible.Cannot remember if you posted that you checked the fan coupling.

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Hi Alan, I dumped the viscous fan in favour of a kenlowe 2 stage fan. I have booked a sniff test tomorrow with a local indy so hope that will give some reassurance. I did get the info from Datatek but the components were not available from CPC. It seems another company now have them in stock (forgotten the name) and I am going to order from them. I must admit I did not check the interior of the hoses. It would have been a good idea considering how much money I have chucked at this car. Don't get me wrong, I love the car, it is beautiful, it is comfortable, it gets admiring looks where ever you go and I am very proud of it. But it is a must that it tows my caravan!
I will keep you all posted after my trip to the indy tomorrow, keep your fingers crossed for me.

I ordered two new rad hoses from Island 4x4 this week, £20 delivered next day and appear to be genuine or OEM in a britpart bag. Wonder if your electric fan has enough cooling capacity? Are your hose rock hard when hot?

Fan should be okay, it is the one for the P38 and is the biggest one they make. I did check that it is running and blowing the right way. The hoses do not get rock hard, it is still possible to squeeze them a little when hot. I am going to our local indy at 1200 midday to get some tests done, that will likely give me a clue (I hope it tells me the head is okay!)

Okay, went to our local indy who charged me £20 (not bad) to do a dye test. The guy who did the test seemed to be a bit confused as to how to do it so had to read the instructions which were not very clear.
So, here are the results. Two chambers, bottom chamber liquid turned green, top chamber very little colour change if any. Indy fitter reckons there could be a very small gasket break or head crack but questions whether its worth the hassle of changing it. If it is a gasket and not VERY clear I would need to get the head pressure tested, and then they don't guarantee there diagnosis! Is there not a pressure test I can get done without major surgery?
Not at all confident so went to my usual landy-fixer who did his own check and said - blollox - nothing there. He said take the stat out (as advised by Datatek and others) and try that. He also felt that the PSI powerbox may have contributed to the problem, causing it to stay in a higher gear too long. I have now put a switch in line so can switch it off. I am going to try the same short journey tomorrow with the caravan without the powerbox. Sorry this is so long.
Bill

Good luck Bill let us know how you get on without the power box.

dean68uk said:

Good luck Bill let us know how you get on without the power box.

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Hi Dean,
switched it out this morning and I must say I prefer it without. I think I will block the EGR and may sell on the PSI powerbox after giving it a trial of switching it in and out depending on how things work out.

enery8 said:

Hi Dean,
switched it out this morning and I must say I prefer it without. I think I will block the EGR and may sell on the PSI powerbox after giving it a trial of switching it in and out depending on how things work out.

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Blocking the EGR is a waste of time and an MOT failure under the new rules if they spot it.

Datatek said:

Blocking the EGR is a waste of time and an MOT failure under the new rules if they spot it.

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I don't know what the best idea is. I bought the PSI box after weighing it up against getting the ECU rechipped. Now I am not sure that was such a good idea.
Dean reckons he gets better hill climbing after blocking the egr which is where I am coming from at the moment.
I am not at all sure these new MOT rules will come in anyway. It is going to take an awful lot of preparation and extra technology (expense) which will be passed on to us on doubt. Sooner we get out of this EU the better as far as I am concerned.
My next MOT is in October so that will give another year before I am effected by the new test, if it materialises.

Datatek said:

Blocking the EGR is a waste of time and an MOT failure under the new rules if they spot it.

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Mine is blocked with a steel 1p as per the BMW forums so it is very discreet and the EGR body remains on the vehicle. It has passed the MOT like this with very low emissions. I have tried mine up the hills by Ringwood on the A31 with and without the EGR blanked as a test. at 60 mph without the EGR blanked it always kicks down but with it blanked it does not. It pulls away better around town too and feels quicker than my old 300TDI Discovery. The EGR is clean and was working correctly for the tests so in my own findings I prefer to run it blanked off. I have an ITG filter fitted too.

Mine is def more responsive without egr. I removed the lot. Will be interesting if mot station wants to assert that m51 engine in rrc had egr in standard fitment and fail me

I can't find any info on proposed changes to the UK MOT that will check for the presence/operation/removal of a EGR system. All I can find is:
Other items – such as headlamp bulb and unit incompatibility, headlamp levelling devices and illegal engine ‘chipping’ – will need further thought before we can get a workable solution for MOT stations.
At present, engine chipping is not illegal, but VOSA seem to think it is. There are legitimate instances where a cars ECU requires it's injection/ignition maps altering, I run a Lotus Elan SE which is tuned and I remapp it to suit. This isn't illegal activity. Nor is plugging in a tuning chip, whether it was internally in the ECU on my GEMS RR, or an external chip on my Freelander TD4. In any case, how will an MOT station know what was standard on a vehicle, what's been added/altered? The internal chip or a re-flashing upgrade isn't detectable in maost cases, even with dealership diagnostics.