I am trying to sort out my plumbing, because I am builing a buggy and the radiator is mounted behind the the seats above my head, I have t use an expansion bottle rather than a header tank as this would need to be mounted above the rad and this would look silly!! The radiator i have has a top and bottom hose and also a smaller connection at the filler neck. The expansion bottle I have has 2 connections in the bottom with one of these having a tube that continues into the bottle. I understand the top and bottom hoses, however, I am slightly unsure of how to plumb in the expansion bottle and the small connection from the thermostat housing?

Any ideas?

i think mine has a seperate water pump that runs off the ignition.... dunno if that will help you at all though, but cant answer your original question

Hi Dilley,

If you want to run the radiator system the same as it was fitted to the Bike, then your radiator does not have enough connections. Obviously you have the large diameter top and bottom hoses. Bottom hose should go to the water pump and top hose should come from the thermostat housing. If your radiator is mounted well above the engine, then you may be able to blank off the extra small hose that comes off the thermostat. This is normally there to bleed off air, as the top hose follows quite a torturous route in the bike by going down before coming up to the radiator. Anyway, if you use all the pipes, the small dia thermostat hose needs to enter the top of the radiator in any position that suits. The expansion tank will probably have a hose coming off the very bottom of the tank. This connects to the filler cap area and will draw coolant in when contracting. The other pipe that you refer to which goes up inside the tank is a breather/overflow pipe. This should go to atmosphere and route out of the bottom of the car in the event of an overheat etc. keep this away from skin as, if it does burp coolant out, it will burn. The expansion tank does not need to be mounted above the engine, it could be lower than the engine if needed. this might make it neater as well.

Hope that answers your question. So, the only pipe you have a problem with is the small thermostat hose. If you can't modify your radiator, connect a pipe to the small thermostat exit and use it to bleed the system when filling. once properly bled, it can be sealed.

cosmick

Hi cosmick, Thanks again, can the small thermostat hose be fitted into the radiator top hose rather than the radiator? I have read that people have had problems with blocking off the small thermostat pipe, some have said that this can cause an air lock when the thermostat opens? I suppose I could remove the center of the thermostat to prevent this? also, I am using the bike water pump as I have a chain drive.

Dilley.

Hi dilley,

I can understand that some people with 7 type cars might have an issue with the small thermostat hose due to the height of the radiator in most 7 type cars being lower or just level with the engine. However, in your case where the top hose will route directly up to the radiator which will be entirely above the engine, I think you will be ok. Due to the way you are mounting the radiator, I don't think that air will be an issue. Even your bottom hose will be above the engine if I am imagining it correctly.
However, if you do want to use the small hose,I think you could put the small hose into the top hose as long as it goes as close to the radiator as possible. Do you have a pipe that you can connect or make a connection?

cosmick

Yes, you have visualised correctly, even the bottom hose is above the engine. I may be able to tee into the top hose, should be 8mm I believe, into 25mm, I will have asearch around...Thanks again Cosmick.

Dilley.

http://www.merlinmotorsport.co.uk/p10759/SELF-SEALING-TEE-WITH-8mm-PUSH-

Hi dilley,

I would try it without the small hose connected as it will look neater without 2 hoses going to the top of the radiator. If you get problems, then you know that you can easily get round it by using the T adapter.

cosmick