Overheating on the V8s

H

hairyrover

Guest
I have a Rover P5b.These cars are pretty well know for overheating and mine was no exception.Rad flush and other attention seemed to help but given a long wait in traffic it would still eventually get hot.
It seemed to have air locks that just couldn't be shifted no matter how many times I tried to fill using rovers method in manuals and handbooks.
I made an extension to fit on the filler cap,approx twelve inches tall. My idea was that although the system has to be filled with the cap off to allow air to escape,there is then a free route for air to get back in and so the system is never 100% certain to be air free.
I tried filling with this extension,the level went up and down and lots of air came out until the engine got up to full temp. I left the extension on until the car had cooled then drained enough water to leave the level an inch or so under the bottom of the filler cap. That was a while back and despite idling in traffic for long periods the gauge stays on normal and as a bonus the heater is much improved.
 
Sounds like a very good idea. I shall try that on my P6 that also have a habit of overheating in queues.
Regards, Barten
 
I will take one later on.It wasn't anything very elaborate,just a piece of rubber pipe that was a good fit in the filler hole.
 
why not fit an expansion tank? my 5 litre 2000 will sit in traffic without overheating-problem on v8 is inherent design flaw that allows for air locks-why rover stated-fill with engine running?--adding tank help greatly
 
I supposed a seperate header tank would help,I had already fitted a catch tank below the level of the filler cap. I think the main problem with the P5b is that with the cross flow rad air bubbles escaping also force out a lot of water and as the level in the rad then drops more air is pulled in.
Since topping up using an extended pipe I have had no more overheating problems.
 
HI, aah you're getting confused between a header tank and an expansion tank. A header
tank is the highest point of the water system, there is usually pipe at the bottom of it
which feeds to a point lower in the system and all vent or bleed pipes like from the carb
tower and the rad go to the header tank to accept the displaced air. An expansion tank
leaves the system on the car intact and can be positioned lower than the rad, within
reason. It has a small bore pipe at the bottom which is fed from the overflow pipe in the
rad neck. The same as the header tank plain cap on the rad and pressure cap on the tank.
Any air or excess water from expansion goes from the rad to the expansion tank which is
usually kept a third to half full, and as the system heats and cools the level rises and falls
keeping the rad full. So what you have done is rig up a temporary expansion tank to purge
the air and then removed it. If you fit an expansion tank you can forget about it as it does
it as you drive it. Header tanks are sometimes difficult to fit in cars as there is usually not
enough height above the engine to make them effective.

Colin
 
as on left side of picture
blackrose_zps83140f03.jpg
 
I'm not confused at all. I have not fitted a permanent expansion or header tank as I don't want to alter caps or plumbing. I've fitted a catch tank that simply vented under the car.
 
hairyrover said:
I'm not confused at all. I have not fitted a permanent expansion or header tank as I don't want to alter caps or plumbing. I've fitted a catch tank that simply vented under the car.
Click to expand...
1 pipe and a tank is not a bad idea as I have seen a few V8s with them-- as my 5litre generates a lot of heat and if it works on mine it will work on a tiny 3500
 
Hi I put my expansion tank on the left hand side with a braided hose running under the 3 row radiator I have had it running and the temperature stayed just under the normal so hopefully when on the road it should behave it's self.
 

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Braided hoses. Very nice indeed DesmoDuke. Have you had your booster vacuum chamber replated also or is that gold paint?

I have always wondered why Rovers in the U.K seem to suffer from overheating related problems on a far greater scale than Rovers running in hot countries.

Maybe the use of the fixed steel fan is very much an impediment to efficient cooling, even when the weather is barely warm by Australian standards, as an example.

The use of an expansion tank I agree is a good idea for the 3.5 litre engine, as they have a propensity for purging coolant.

Ron.
 
Nice placement of the expansion tank. I assume you have made up a special bracket for it? What kind of bottle have you used? Some good ideas for my project Rover here, Thanks!
Regards, Barten
 
When mine was 3.9 rover I never had any problems with overheating--only when put Buick 300 in it I had problems Had to lift bonnet(hood) at rear a little and NADA scoops to displace the heat---now can sit in traffic for ages and temp never goes above half way on gauge :D
 
Hi It's been painted gold I didn't fancy the silver look, The expansion tank originally came off a Morris Marina I had it on my 2200 TC the only one that came up for sale was a brass one so that ended up in the 2200 TC. I just folded some 4mm ally plate to fit the bolts for the front bumper irons.
 
Hi some photo's of the expansion tank bracket.
 

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