river
New Member
Posts: 7
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Post by river on Aug 1, 2020 9:42:47 GMT
Hello. I hope someone may be able to help with an overheating problem.
I have a MkII running hot when under load e.g. going up even a slight incline/hill (usually 40 - 60 mph) or over about 2500RPM. Needle goes up to the red quite quickly, yet returns to halfway (or just below) when cruising back down hill or at idle. Electric fan cuts in early and stays on for most of the time when driving (no viscous fan fitted). It then stays on for a few minutes after stopping.
My set-up is:
Recent engine rebuild with new water pump, coolant hoses, 82 thermostat, voltage stabiliser
Viscous fan replaced with Revotec
Cooling system flushed/reverse flushed
TR6 spoiler and filled gaps around radiator
I keep reading stories of how people never see their needles rising above halfway, and with my car in seemingly good running condition I am out of ideas what to try next. Of course the gauge could be faulty, but I don’t think so as the voltage stabiliser is new, and also the needle stays at about halfway when at idle/in traffic when hot. It is only when driving does it start to rise.
Any help appreciated. Thanks
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bullstarz
Full Member
I don't believe in miracles, divine intervention or good luck............. I rely on them.
Posts: 135
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Post by bullstarz on Aug 1, 2020 10:34:32 GMT
Check the base setting of everything, timing,fuel and ignition, and that the vacuum side of the dizzy is working. Check all the plugs, they may show whats going on.
It seems to be running lean. This could be the fuel mixture too weak or timing is well off or not changing with the load. If the float levels are wrong in the carbs they cause the engine to run badly or even if your jets slightly blocked. There could even be a leak after the carb on the inlet.
"Mrtempler" had a similar thing and It may have been the low/lack of oil in the dampeners in the carbs. Which allowed the throttle to open to quick leaning off the mixture.
Its a case of trail and error until you find the guilty party.
There will be loads of advice available from other members but just update us with what you do and find.
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Post by staggard on Aug 1, 2020 10:35:36 GMT
This is a tricky one, as I would seem you have covered most things. I guess first you must establish that it is over heating maybe with an infrared thermometer, check there there no airlocks in the system,I have also seen a front mounted electric cooling fan sucking instead of blowing, a faulty stat not opening fully. I cant think of any more easy things to check. It sounds like there's a restricted circulation so then is there a waterpump mismatch impeller and housing and has the housing been shimmed up correctly. I personally am not a believer in doing away with the viscous fan a it keeps a constant airflow through the rad and also keeps the under bonnet temperature down. Somebody will be along soon to add their ideas. Good luck
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Sapphirestag
Full Member
Letting your tyres down at the moment. I was also a target of the Fiefdom controlling the SOC forum
Posts: 129
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Post by Sapphirestag on Aug 1, 2020 13:38:26 GMT
All good sound advice above, also these things need checking in the hope that it is something like a timing issue before you dig deeper. Have to say though, these are also the early symptom's of the beginning of a head gasket issue. Lets hope not though.
Another thought is do you have one of these aftermarket header tanks? there is at least one type out there which is incorrectly plumbed in if you follow the instructions that come with it and it allows a small amount of hot coolant to be feed back in to the engine.
Good luck and keep asking questions, were all here to help even if some of us seem a little uncouth.
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Post by staggard on Aug 1, 2020 14:08:36 GMT
I see the engine has just been rebuilt. And it has brought it to mind when Ian mentioned head gasket. In my experience the BGA head gasket need to be re torque on a regular basis, immediately after the first start up, then I re did mine once a week for about three weeks before it stopped compressing.
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Post by Flying Farmer on Aug 1, 2020 19:24:19 GMT
Was it getting hot before the rebuild? If it was it could be a silted up radiator.
If it was ok before the rebuild it must be something that was changed. My favourites would be faulty thermostat not opening far enough (had one like that a few years ago)or a mk1 thermostat with no foot fitted to the mk2 manifold.
Incorrect water pump impeller/combination is another one
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Post by staggard on Aug 1, 2020 21:36:19 GMT
Hi is this Niel from "flying farmer "
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Post by grolly on Aug 1, 2020 22:26:54 GMT
Hi is this Niel from "flying farmer " No, you’re staggard. What are you on? Pls share. |
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Post by staggard on Aug 1, 2020 22:59:19 GMT
What ever is is you won't be able to afford it
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Post by staggard on Aug 1, 2020 22:59:36 GMT
Was it getting hot before the rebuild? If it was it could be a silted up radiator. If it was ok before the rebuild it must be something that was changed. My favourites would be faulty thermostat not opening far enough (had one like that a few years ago)or a mk1 thermostat with no foot fitted to the mk2 manifold. Incorrect water pump impeller/combination is another one |
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Post by staggard on Aug 1, 2020 23:02:22 GMT
Ok I have the forum police on my case so I hope I have got this right this time. Question Hi Neil are you flying farmer from the SOC forum.
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Post by Kryten on Aug 1, 2020 23:38:30 GMT
I’m with Neil - sounds like lack of flow across the radiator, Mk1 stat in Mk2 manifold, wrong pump/housing combination or possibly the rebuilt water pump impeller slipping on the shaft.
If you have the header tank from a certain supplier, with the hose T’d into the water pump hose, then that can also bypass some flow from the radiator
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Post by Flying Farmer on Aug 2, 2020 4:58:58 GMT
Ok I have the forum police on my case so I hope I have got this right this time. Question Hi Neil are you flying farmer from the SOC forum. Yes, it is me. Wouldn't accept flying farmer |
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Sapphirestag
Full Member
Letting your tyres down at the moment. I was also a target of the Fiefdom controlling the SOC forum
Posts: 129
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Post by Sapphirestag on Aug 2, 2020 9:19:38 GMT
Another quick check you could try is to see if there is and difference (would be small) with the heater valve open and then closed. That would point towards a circulation issue as well. Apologies for my earlier post, I didn't read your original post fully stating what had been done recently. I blame it on the alcohol.  I'd also be tempted to refit the VC. |
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Post by misterbojangles on Aug 2, 2020 10:00:15 GMT
Ok I have the forum police on my case so I hope I have got this right this time. Question Hi Neil are you flying farmer from the SOC forum. Yes, it is me. Wouldn't accept flying farmer It would have Neil had you not left a space between the 2 words. |
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