Archived Message
Is my engine running hot?
I have only owned my RV8 for a few months and whilst I enjoy driving it at every opportunity I am not very technically minded and wonder if I am worrying unnecessarily. The engine seems to get extremely hot and even after about 15 minutes of driving can hardly bear to put my hand on the bonnet. Is this normal for this engine? I have carried out some the simple tests suggested in the threads on the subject. The fan cuts in ok, I have sqeezed the top hose when hot and cold and the pressure appears ok and the coolant level and oil level is ok. The guage never moves much past 12 o'clock but apparently this appears to be normal. Should I get it checked out?
Malcolm Roots
01/07/2012 @  19:27
Under topic: RV8
Archived Reply(ies) received for this Message
Is my engine running hot?
The simple answer is yes you must get it checked out. I was talking to Clive Wheatley at MG Live last weekend and he was describing a car they had worked on which had shown similar symptoms. The owner unfortunately continued to use the vehicle before asking for help by which time he had cooked the engine and it needed new head gaskets.

It is entirely possible this is worse case scenario of course but do continue to make use of the search facility on this website. Type in a keyword and you will be directed to a multitude of help and advice. Incidentally, there is a workshop note on modifying the temperature gauge so it reads more accurately.
Ian Quarrington
02/07/2012 @  03:34
Is my engine running hot?
Do check out the Tops Tips for a new RV8 Owner - the link is at the foot of the V8 website homepage. One recommendation is to check the expansion tank is not overfilled.
V8 Webmaster
02/07/2012 @  06:44
Is my engine running hot?
The RV8 does develop a huge amount of heat anyway. When you stop, did the header tank overflow violently? If so there is air in the system which has to come out. See RV8 note on this.
The answer is to take a closer look at the radiator cooling function.
If you live anywhere near Clive Wheatley he would help. Otherwise can only advise getting the radiator checked (gunge and sediment in the bottom area cleaned out).
Peter Garton
02/07/2012 @  15:32
Is my engine running hot?
I had my radiator refurbished with a new core,adding an extra row, which helped cooling, The Norwich Burblers also changed the temperature gauge for me, which gives the actual temperature and does not whizz straight up to 100 when cold. I am sure the more technical RV8 owners will explain why!
I also have had invaluable advice from Mark Adams over chipping and plug's, they too have helped. Yesterday on a 50 mile trip to the Anglia MGCC picnic, driving with enthusiasm the temperture never went over 90 although the car did.I have also had made from stainless steel a new grill which I believe allows a better air flow to the engine! I had my radiator refurbished at Express Radiators Norwich, and for memory they charged £130.
Michael Reavil
02/07/2012 @  16:14
Is my engine running hot?
Michael is right about all this but I doubt you need to go to all the trouble he's gone to re radiators. Suggest you give the rad a good flushing and replace with new coolant and a new big bore thermostat. make sure you don't have any trapped air in the system. BTW, Mike couldn't possibly exceed 90 officer, as he has a bad knee!
Terry Starkey
02/07/2012 @  16:39
Is my engine running hot?
Although the RV8 does indeed have a tendency to run hot, as any passenger during a trip on a summer day will confirm, the car should not be that hot that you Ďcan hardly bear to put your hand on the bonnetí. It does sound as though you have checked that you do not have air trapped in the system and I assume that you are certain that the water pump is operating correctly. Overheating can only be the product of poor coolant flow and it is for this reason that many of us have fitted the big bore thermostat. Frankly, I have my doubts that this makes much difference but we need all the help that we can get with this issue. Do also take note of the note from the webmaster regarding overfilling of the expansion tank. This is a common problem because it does look so very empty when the engine is cold and the instinct to add more coolant overrides the fact that the book value is correct.
With regard to the matter of the fan cutting in, this will only be of interest when driving at speeds that do not allow a good flow of air through the radiator and, of course, the fan substitutes for the lack of airflow by road speed. As Ian Q has pointed out there is a very worthwhile mod that allows the water temperature gauge to read the actual temperature of the engine. With standard wiring the gauge will only read what can best be described as on- off with the on being noted by the needle pointing at the 12:00 position, as you have already observed. A fan switch thermostat, available from Fiat dealers for about £20, that switches on the fan at 97c, instead of the standard 107c, which is far too hot, will also be a very good investment. They are very easy to fit and if you are in the area of East Anglia I will be very happy to do it for you, for free of course.
However, back to the problem. I would suggest that you begin by flushing the coolant being careful not to put very cold water into a very hot engine of course. It might be an idea to get this done properly by a qualified garage if you are mechanically uncertain.
If that fails then it is most likely the radiator. There is a better radiator available, from Clive Wheatley as Ian has already mentioned, but any good radiator repairer should be able to modify the one you have, as Michael Reavil has done.
As I write this note I do know that John Cumming is in the process of fitting a special radiator to the car of Mike Sutton and, were I in your position, I would take direct contact with John Cumming for advice. John is an extremely kind man, very generous with his knowledge, and will give you the very best advice.
Angus Munro
02/07/2012 @  19:03
Is my engine running hot?
Thank you to everyone for your comments and advice. As I suspected all is not well. There were a number of comments regarding the expansion tank but the coolant level is ok. My first job will be to flush out the radiator and replace the coolant and if this doesn't cure the problem take it to a specialist to check it out. I noted from the car's history file that a new radiator was fitted by Fisher services in September 2008 when the mileage was 43315. The current mileage is 48100. I will let you know the result when the problem has been identified and cured
Malcolm Roots
02/07/2012 @  21:53
Is my engine running hot?
Terry and Angus mention a big bore thermostat but tease us by not giving any details whatsoever - Iíd be interested to know the manufacturer and/or who supplies them.
Geoff King
03/07/2012 @  01:46
Is my engine running hot?
Perhaps they mean a "Wahler" thermostat.I have one fitted to my car after a recommendation by a TVR owner.Available in different temperatures from many sources I think.
Dennis Hodge
03/07/2012 @  17:22
Is my engine running hot?
Geoff, and others. The reason that I didnít mention the make or source of the Big Bore Thermostat is that I simply didnít know. Although I had one in my hands I put it into the car without looking at any details. John Cumming, being the man that he is, sourced a few of them and then offered them to chums at a local natter night.
So, this morning I had to telephone John and he very kindly provided the following information.
The source of the, 82C, thermostat is,
The thermostat diameter is 31mm as against 27mm for the standard one. Part number is E2027 and the price is £10.20 inc VAT plus post. An uprated gasket is also available, part number E1095U at £2.28 inc VAT plus post.
Malcolm, we donít want to put Johnís contact details on this post for obvious reasons but, rest assured that plans are under way for John to contact you privately.
You may trust me on this; you will have fallen into very capable hands.
Angus Munro
03/07/2012 @  18:14
Is my engine running hot?
Angus, thank you very much for your help and also the offer to fit a fan switch thermostat. It's very kind of you. Unfortunately I live in Kent and I will not be undertaking any long journeys until I have sorted the problem. Looking forward to hearing what John has to say.
Malcolm Roots
03/07/2012 @  21:09
Is my engine running hot?
Thanks Angus, looking at the pic on Clever Trevor website I think Dennis is correct, itís probably a Wahler 82degC thermostat Ė good quality, as fitted to some Porscheís (and Daihatsu, Honda, Suzuki, Toyota etc.).
Geoff King
04/07/2012 @  05:33
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