XR4Ti Coolant Recovery Bottle always full

[cmouta]

I'd love to delete this thing and have seen a ton of people do it but mine is ALWAYS full of fluid. Is this indicative of a problem? I've never had an cooling/overtemp issue. I changed the radiator to a used audi 5000 unit 4 years/4k miles ago that had been in service without issue to someone else. I just changed radiator caps to a new style with venting lever, no change. I've burped the coolant lines appropriately several times. I seem to lose fluid to the coolant recovery bottle and have to top off regularly. My last track day, the bottle was half full before the event, and so full after the event that pressing the "vent tab" on the radiator cap made the recovery bottle puke fluid onto the floor. Any suggestions?

[zxr250cc]

Hi all,

Mine began to act like that after it developed a small crack leak in the bottle. Prior to that it was normal with the full line maintained when cold. The loss of pressure due to the small leak let the bottle fill up. Perhaps there is a small pin hole leak?

Cheers

[hEaT]

Verified the cap is good? What pressure rating is it?

[cmouta]

Not sure what was on there before but currently its a Stant 10330 16PSI cap. I didn't test it(not sure how without specialized equipment, I should look into rentals) but it was brand new. I've read all the threads about them failing at the lever mechanism but I'd expect it to hold up for at least 200 miles.

Am I looking for a leak above the coolant line or below? I'm not leaking any fluid at the bottle but definitely have a few coolant hoses with some weeping happening. I'm trying to wait until winter before I pick up a new radiator and hoses for a full cooling system overhaul.

[zxr250cc]

Hi all,

Mine has a small crack leak on the top surface of the bottle. It is about an inch long and has resisted all efforts to patch it so far.

[Ed Lijewski]

"... but definitely have a few coolant hoses with some weeping happening. I'm trying to wait until winter before I pick up a new radiator and hoses for a full cooling system overhaul.

You likely already found your problem.^^.

YMMV

[eaton53]

Hi all,

Mine has a small crack leak on the top surface of the bottle. It is about an inch long and has resisted all efforts to patch it so far.

JB Weld fixes everything. I'd try that to fix a crack in the coolant bottle.
We used it to patch a cracked radiator on a Celica All-Trac Turbo. Repair outlasted the car.

[thesameguy]

"... but definitely have a few coolant hoses with some weeping happening. I'm trying to wait until winter before I pick up a new radiator and hoses for a full cooling system overhaul.

You likely already found your problem.^^.

YMMV

Yep. If pressure isn't maintained in the system, you're going to have a bunch of problems. Cooling systems can't leak and still work right.

Also, not running a bottle is madness! Don't do that.

[zxr250cc]

Hi all,

I tried the clear JB WELD but it failed. I have the premixed black stuff that you knead for a bit before installing to try next. The bottle is polyethylene, I think, and does not like to have anything stick to it.

Cheers

All had a blast at Carlisle?

[cmouta]

"... but definitely have a few coolant hoses with some weeping happening. I'm trying to wait until winter before I pick up a new radiator and hoses for a full cooling system overhaul.

You likely already found your problem.^^.

YMMV

Yep. If pressure isn't maintained in the system, you're going to have a bunch of problems. Cooling systems can't leak and still work right.

Also, not running a bottle is madness! Don't do that.

It can't be THAT madness. Ford deleted it in later XR's themselves.

I've tightened as many clamps as I can access but alot are starting to crack the hoses. I think I'll rent one of these pressure testers just to make sure. I need to stop buying $100 tools I only need every 5 years

[thesameguy]

All XR4Tis always had a coolant expansion tank - initially on the right side, then on the left side.

[cmouta]

All XR4Tis always had a coolant expansion tank - initially on the right side, then on the left side.

Ah, I'm not talking about the coolant expansion tank. I'm talking about the coolant RECOVERY bottle. It's the smaller bottle that is plumbed to the cap neck of the coolant expansion tank as shown in the diagram in my initial post.

[thesameguy]

Ah, got it. The bottle is mated to the tank or, rather, the cap on the tank. Earlier cars use a more antiquated partial pressure (aka normally open) cap and later cars use a more modern full pressure (aka normally closed) cap. In the early system, the cap allows movement into and out of the reservoir until there a sudden rise in pressure that closes the cap and starts pressurizing the system. This is how old cars worked, the idea being that the system remained at atmosphere until there was a reason for it not to. Back then, coolant could get pushed out of the system onto the ground - and that's bad for more than one reason (like, environmental and functional). Later on, recovery bottles were added to capture that coolant and return it to the system once cooled. In the later system, the cap remains closed until there is an overpressure scenario, which should basically never happen. Constant pressure systems are more effective and efficient, and by the late 80s or early 90s virtually everyone had switched over.

Here's a good article:

https://www.centuryperformance.com/cool ... asics.html

The takeaway is that you can't just delete the recovery tank - you gotta switch out the reservoir too. Doing that is definitely an improvement - constant pressure systems simply work better.

*But*, either way, you can't have leaks in the system or you get a double order of fail - the system will not properly pressurize and be more prone to boiling over as the heat carrying capacity is reduced. Somewhat ironically, small leaks in a hose will increase the potential for leaks at the bottle. The above article addresses some of that.

[John Brennan]

Thank you, great info... I have had several XR's, from an '88.5, to an '85, and two 89's (one was my nephew's, then my son's, but you know who fixed 'em, right?), and I have to say, the '89 system with the jug on the cold side and the reduced number of hoses, connections, etc., is a VAST improvement over the Early system(s).

[thesameguy]

The early system was a throwback for sure, but we're just talking about the reservoir's function. The actual meat of the system never changed. You need a supply to the system and a return/overflow from the system. At the end of the day, all you need is some bottle that performs that function. My opinion is that the dual return system (one from the head pipe, the other from the radiator) is a good concept and ideally you want to preserve that, but it's not necessary. Similarly, the bottle on the cold side is nice, but IMHO there isn't truly a reason to do that... plastics today are very good and people squeeze these bottles in wherever they can; a modern bottle should hold up on the hot side reasonably well. The VW tank I've been using has made it four years without issue.