Vortec 5.3 coolant expasion tank (1 Viewer)

[cruiser7773]

OK guys, so here's the deal- I've done a little searching and haven't found anything on this specifically; I hope I'm not doubling up. I have a 2002 Vortec 5.3 with a Ron Davis radiator specifically built for the engine to fit in the factory FJ40 mount. My question is, do I really need to run the expansion tank if I have a pressure cap on the radiator. Can I just replace the hose that goes to the expansion tank and heater with one that just goes to the heater?

Currently the expansion tank is in the system, but it is at about the same level as the radiator and I have a hell of a time getting all of the air out of the system. I would also like to use the space the tank sits in for something else.

What do you know? Please educate me. Also, if I were to remove the tank, what psi cap should I run on the radiator?

Thanks guys.

 

[fieldsken1]

you dont need a tank at all older cars never used them. why dont you just buy a smaller tank??? mine is on the firewall. i also have a ron davis rad. it would be nice to have picture

 

[Medusa]

An outstanding tech article on this subject was prepared by Billavista on the Pirate Board.Pirate4x4.com - The largest off roading website in the world.

I am not sure what you mean by "expansion" tank. Are you talking about a simple, non-pressurized overflow tank like the one pictured by fieldsken1 or a pressurized surge tank connecting the heater core with the radiator?

Whether you use a surge tank or an overflow tank depends primarily on whether or not your radiator has a cap. Here are two simple diagrams taken from Billavista's article showing the difference between a system with a tru surge tank and one with a simple, old-school overflow tank. If you go old-school a 14 psi cap is common.

 

[cruiser7773]

Medusa,
Thanks for the diagrams, the top one is exactly how my system is set up, except my radiator does have a cap. Should I remove the pressurized cap from the radiator so it can vent freely into the "surge tank?" And just to be clear, since I have a cap on the radiator, can I remove the surge tank from the system?

 

[Medusa]

It sounds to me like your radiator was not designed to use a pressurized surge tank. If you keep the surge tank you will need to make sure that the cap on the radiator is rated for a pressure higher than that on the surge tank AND that the hose and fitting connecting the surge tank to the radiator is appropriate in both pressure capabilities and volume of flow. I am not sure that the small tube on the radiator filler neck that normally serves as the overflow meets these criteria.

And Yes, if you use a normal radiator cap and overflow you can remove the surge tank and route all of the plumbing as in the lower diagram.

What are you doing with the steam port?

 

[cruiser7773]

other than having a fill cap and normal vent port, the radiator was made specifically for my 5.3 vortec. The steam port vents into the top of the radiator. After reading the article you suggested, I think the best think I can do until I replace the surge tank with a smaller one I can mount higher than the radiator, is to remove the pressure cap from the radiator and allow it to vent freely into the surge tank. They are currently mounted at about he same level; hopefully the pressure differential will move all the air/steam into the surge tank were it belongs.