Classic cars forum & vehicle restoration.

Bayliss Thomas · Joined: 25 Sep 2009 Posts: 557 Location: SUFFOLK

I've also asked elsewhere this question, when I put my vintage car into harder driving it has an tendency for the radiator to boil after an couple of miles or so. When I drive in an normal fashion all is OK. i ASSUME THAT THE RAD' IS BLOCKED WITH CRUD AND POSSIBLY THE WATERWAY IN THE BLOCK ALSO. Anyone tried Holts flushing solution, bearing in mind my vintage car is fitted with an aluminium head. Thanks for comment/advise.

victor 101 · Joined: 03 Apr 2009 Posts: 446 Location: East Yorkshire

Hi Bayliss, have you back flushed the system? I have never had any luck with Holts stuff myself, but im sure others will disagree.

michael1703 · Joined: 22 Jul 2009 Posts: 349 Location: suffolk

is the fan belt tension correct? if the belt slips it will overheat

is the pressure cap the right poundage and is the rubber seal good?

is the timing correct?

Roger-hatchy · Joined: 07 Dec 2007 Posts: 2135 Location: Tiptree, Essex

Another possible cause is a leak somewere in the induction side.

I had the same problem and found that there was a slight leak passed the manifold.

Or it cold be jetting making it run too lean when driven hard.

Just another thought

buzzy bee · Joined: 23 Nov 2007 Posts: 3382 Location: South Cheshire

Hi

If you are still allowed to use your hose pipe, flush the block, down wards, and then upwards for 15 mins eash way, and then the same for the rad, both up and down, 15 mins each way. Check the fan belt, pump if you have one.

Also blow the outside of the rad through well with some air from the compressor, incase the core is dusty, any dust on the core will cause insulation to colling fins etc.

Cheers

Dave

Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

Keith D · Posted: Fri Jul 09, 2010 1:21 pm Post subject:

BT,

Assuming that you have done the usual checks of water level and that the cooling fins are not disintergrating, I would be reasonably confident that if your engine temperature is speed related then in fact it is your radiator partially blocked.

I had to drive a modern 1000miles to the northwest of Western Australia so therefore anticipated a long days run at about 70-80 mph. I found that I had to keep my speed down to no more than 50 mph to keep the thermometer out of the red. On that journey through the Outback, I only passed near two towns and was therefore very apprehensive of ruining my engine. Frequent checks assured me that the water level in the rad was not dropping. I broke the journey over two days and kept my speed down. I arrived safely without wrecking my engine! (And probably saved quite a bit of petrol!)

On arrival in Karratha, I removed the radiator and had both the top and bottom tanks opened and the core rodded through. There was excessive build up of calcium inside the tubes. The tanks were resealed and my overheating problems were over.

If your vintage car has a cellular radiator, then get it rodded through. However, if it has a honeycomb radiator, then things are not so easy. You will have to flush it through with caustic soda which is nasty stuff!

Cellular radiators are a lot more efficient than honeycomb radiators. A trick that I have often seen done here in Oz is to have a new cellular radiator made up for your vintage car, then slice a thin veneer off your old honeycomb radiator and solder it to the front of your new cellular rad. Nobody will then know that you've "cheated"!

Good luck! Keith

michael1703 · Joined: 22 Jul 2009 Posts: 349 Location: suffolk

another thought, impeller blades might have corroded

Bayliss Thomas · Joined: 25 Sep 2009 Posts: 557 Location: SUFFOLK

Many thanks for all the tips and info'. Yesterday I used 'Wynn' coolant flush two tins as the radiator holds so much water. Its an acid free solution so no risk to alloy. Thought may as well start with the easy way! next step is I will use my Bro's air compressor and give the honeycomb an blow through. Change my engine oil for an slightly heavier grade (sae40 in place of sae30).

See how things are after this.

Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

You never mentioned what your "vintage" car is. SAE 30 sounds a very low viscosity for any "vintage" car in the summer. Generally the practice and recommendations used to be to use SAE 50 in summer, changing to SAE 30 in winter.
Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

Nic Jarman · Posted: Sat Jul 10, 2010 8:11 pm Post subject:

I changed the oil in my midget to 10/40 semi and cured the overheating problem. If your engine is in good condition this will not be a problem and it may even keep it good for longer. Remember the only reason 20/50 was recommended was because there was nothing better. As long as you have good oil pressure it's OK. I must go and put the hot coals in the clothes iron after pummelling the washing in my local river.
_________________
1936 Morris 8 Series 1
1973 MGB roadster
1977 MG Midget 1500
Dax Rush

Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

MVPeters · Joined: 28 Aug 2008 Posts: 822 Location: Northern MA, USA

It's actuallly here & well worth reading:

http://www.realclassic.co.uk/techfiles/oil030319.html

Does anyone have any hands-on experience of synthetic oils in vintage motors?

Mike
MVPeters@comcast.net

Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

Sorry I made a mess of that link. I've put an EDIT on my original post. Thanks for correcting it. The article shoots down lots of mis-conceptions and myths about oil, written by a well informed and qualified person.

Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

Keith D · Posted: Sun Jul 11, 2010 11:53 am Post subject:

Jim,

I'm not nit picking, but Austin Sevens most definitely DO have oil pumps!

Keith