cooling system question

[oly02]

I have just fitted an upgraded radiator to my 97 D1 SE7 and have found the following, The temp rises as expected and the thermostat is working as advertised. there is a good flow rate of coolant and the system stabilises temp as expected at about 1/2 on the gauge. there are no leaks and everything runs fine. but the system does not build up any pressure after running for 20 mins. I can remove the header tank cap while the engine is running and while the coolant is hot, there is no build up of pressure as the cap is undone?

Any Ideas or is my cooling system just working well?

 

[joey]

As long as it flows the fluids it may not need to build up pressure (you say it is an upgraded radiator, as in custom or just new?)

 

[oly02]

Custom Radiator

Joey, I had custom 4 core radiator made using the matrix from a truck radiator. The tubes inside the matrix are about twice the diameter of the original and it has much heavier cooling fin material.

The old unit was repaired following an impact with a kangaroo a few months ago, it handles the australian heat fine but when the temp is over 40 c it was ok on the open road but was begining to struggle in trafic. I explored every option available and looked at an aftermarket 4 core unit compared to this unit. it has a lot more fluid flow ability and should work better

 

[greg409]

Oly - the reason a cooling system is designed to pressurize is that water (the basis for cooling) boils around 210 deg. F. (at sea level)

If you pressurize it, the boiling point rises, if you add ethylene glycol (antifreeze), it rises more. (best @ 50/50 mix) (more glycol will actually lower your boiling point)

So, when you have 50/50 @ 15psi in your radiator, you're good for about 240 deg F.
if you have 0 psi & a 100 degF. day with a load on (your truck) - it might overheat.

The coolant expands, so if you fill it when it's @ ambient temp, it WILL build pressure upon warmup.

If you have alot of volume & a lot of expandable air space, it might not build up much pressure.

My concern would be boiling when you really don't want it.

Vent as much air as you can, check your cap, you DO want pressure.


luck,greg

 

[beemer]

Joey, I had custom 4 core radiator made using the matrix from a truck radiator. The tubes inside the matrix are about twice the diameter of the original and it has much heavier cooling fin material.

The old unit was repaired following an impact with a kangaroo a few months ago, it handles the australian heat fine but when the temp is over 40 c it was ok on the open road but was begining to struggle in trafic. I explored every option available and looked at an aftermarket 4 core unit compared to this unit. it has a lot more fluid flow ability and should work better

Those damn Roo's cost ya a radiator, hope not much grill damage sorry to hear about this but maybe a good thing. First off congrats on adding a larger capacity radiator one can not have enough reserve radiator capacity. I have a custom built one in my 95 5 speed plus the 4.6 is making more than stock HP, TQ and heat. I'm rock solid on the temp gauge at 35-40% of the scale, it will climb if I block off the radiator with cardboard, the gauge reads properly. The thing I have found out is even going thru 3 brand new stats all three opened up at different temps as well the amount they opened at 185*F. This from borrowing 3 new stats from my trusty LR parts friend. After the stove temp test in a *** of water with a Fluke 52 meter I discovered the Rover OEM stats are all over the place in temps and function. I picked the best one then returned the others the next day back to my dealers parts department. They are back as NIB. My engine temp will climb from 40% to 50% max with AC on in 0-4 mph 95*F temp weather in traffic. Rather solid. I once had a replacement stat take a dump and only open between 1/6" to 3/16" with 4K miles from new. Yes the temp was all over the place and rather quickly. The best BTU engine heat removal is 100% water but not going to happen without rust and the aluminum rotting away.
I run 45% to 50% max anti freeze mix with distilled water. best with the radiator out is add a petcock drain valve to the lower radiator neck for easy future radiator drains, removing the lower hose is a POS and a flat stupid Rover idea. These are not perfect vehicles. I must add you do need your recovery tank checked as the black ones will crack as well the "better replacement white ones" plus you need that pressure cap checked. You can pull it out of the cap and check the rubber flappers for seating of the pressure as well vacuum when cooling down. If FURBARed replace.

Joey; I haven't forgot you with my intake and injection project, I need my son to bring home from college his flash cards to download my pictures and send to you. BTW it's a joy to drive this D1 in town now with stop and go traffic, motor doesn't care which gear it's in, pulls even in second with the tach bouncing to zero rpms, clutch then throttle later no stalling out. A rock crawling pulling motor that will still spin 5,800 rpm's. This is like a second large step again I chit you not, first from a 3.9 to a 4.6 again the same big step with what I created with my ideas to improve on what I have. The results make me laugh every day, more wheel spins in the wet I must now retrain my right foot.

 

[oly02]

Radiator

Thanks for your imput guys, I appreciate your thoughts. I understand thet the cooling system should build pressure, just heating the fluid will make it expand.

I will check the cap to see if it holds pressure when i am at work. i have the gear there to do it. I cannot see any leaks or hear any after i drive it. have taken it out for about half hour so far and ran it with ac flat out. it runs fine and does not give any indications of any problem. this makes me worry. I have owned it long enough to know nothing on this machine is this simple