I've got a small coolant leak somewhere I need to ferret out. So I went and rented a pressure tester from AutoZone... erm... now what? Clearly it attaches to the coolant reservoir, but is there a hose I need to pinch off? Is 20psi. correct? Hot or not? I couldn't find a good thread on this, so tips and tricks welcome. Thanks!

 

The pressure tester I have 'rented' from Advance AP had 19 different connection fittings and I had to use the universal one for the Jaguar. As long as the connector seals the reservoir tank before the overflow tube it will pump up. Yes, 20 lbs is appropriate. Working on a cold engine is always easier and it doesn't matter.

Pump it up and the leak will magically appear. Good luck.

 

I would use the pressure cap's rating as a guide to setting pressure for the test.
Should be around 12-13 PSI.
A higher pressure could cause a slow leak to become a gusher.

 

Also watch for coolant hoses that inflate like balloons when pressurized...they are time bombs.

 

Chris, let me know if this works for you. I am starting to slowly drain the tank too and can't see any leaks. Looks like I may need to get one from the 'zone as well.

 

You got it, Mike. I'm hoping to get this investigated this coming weekend or over the holiday. Will update back then!

Thanks, all. Standby...

 

Ok, I've got the adaptor I need. Pump pump pump pump... nothing. Are you guys sure I don't need to pinch or close off something? The adaptor and seal with gasket are tight, so there must be.

An important aside for the record... is your radiator fan assembly attached to your radiator? Mine wasn't! It was hanging loose an inch from it in front of the belts! It appears this just simply lifts up and drops back on over the radiator shroud, which I did. Firm enough, and I didn't see any screw holes to attach it further. Amusing.

If you put hands on the radiator shroud, wear gloves. It's fiberglass (think about it). I'm now nursing several micro wounds.

 

Went to the local Autozone (conveniently located across the parking lot from the Carrollton Motor Club show today) and got the pressure tester. Got home and discovered the correct fitting for the Jag expansion cap was not included.

However, all was not lost. I got it as tight as possible and pumped. Never got near 15 psi, but it did force coolant out underneath the car. Looks like it is coming from the passenger side (right side for the Brits) behind the wheel. isn't there a recovery bottle inside the wheel well liner? Or is that on the other side?

Either way, what hoses are in that area and what should I look for?

 

Is it the AZ on Trinity Mills? That's where I got mine from, but it requires the metal screw fitting adaptor that comes separately ($30) in a small red plastic case (there are two different fittings in there, one works). Also loaner.

There IS an overflow bottle exactly behind the US passenger/right front wheel behind the liner. I read somewhere about that and saw a photo of it, and I think that's the line that needs to be pinched off, but I can't discern which hose this is coming off the reservoir. I'm going to look again...

 

No, I went to the one on Josey and Rosemeade. Got the extra box with a metal fitting, but it did not have a screw fitting. Might try the Trinity Mills store if I need it again...assuming you took it back.

Waiting on it to cool down some before I try to tackle the recovery bottle. Looks like wheel off, liner off, to reach it. Sound right?

 

Does your loaner tools have a universal cone shaped rubber fitting? The one I got did. It goes into the reservoir neck and seals it before the hose to the overflow bottle. That's what I meant by nothing fit the Jaguar. All standard connections either did not fit or left the overflow tube exposed to the pumped up pressure.

 

Ha, nope I still have it- here's a photo of it. It's like dark red anodized aluminum or something. One obviously fits, the other doesn't. As soon as I ID it, I'll let you know when I'm returning it. Correct on wheel and liner off to reach it- there's a lot of space in there!

But - from this vantage point - does anyone know which line from the reservoir goes into the overflow tank in the wheel well? Top? Left? Right?

 

Just pinch off the overflow line with a pair of needle nose vice grips.

 

Argh! WHICH ONE?

 

Thanks for the pictures. No the kit they gave me only had the two adapters shown in the main box in your picture. The small red case with the screw-on adapters were missing. They gave me an extra box, but it was just another plastic adapter.

Decided to go eat and see my daughter tonight, so will tackle this first thing in the morning. Wish me luck that it is just a loose hose or one that I can splice.

 

Looking at the above pic, pinch off the rubber line on the left. That is overflow coolant line. It connects to a hard line that runs across the back of the firewall into the recovery tank which located behind the fender liner on passenger side.

As Testpoint noted, the pressure tester cap does not go deep enough into the coolant tank neck to seal off the small orifice leading to the overflow recovery tube. Hence you can pump the tester all you want, but the system will not pressurize. Pinch off that hose and see what happens.

There are four (4) hose outlets off the coolant tank. A large hose (5/8" ID under the coolant tank) going down to the Octopus; one to the top of the T-stat housing, one to the Throttle body, and the one I am talking about that goes to the overflow recovery tank. On early models, like my '97, there is an additional small hose leading to the top of the radiator at the drivers side.

 

Same here, Mike- let us know. I'll be tackling it this evening. Thanks, Gordo! Perfect.

 

Didn't know to pinch off overflow line. The drip I saw from under the recovery bottle was likely from not clamping off the overflow tube. Thanks to Gordo for that tip.

When I got the car on jack stands and I took off the wheel, I noticed coolant running on the ground. So, under the car for a look-see.

Appears that the leak has been dribbling on the right front suspension bits. This is directly under the top radiator hose and there seemed to be discoloration on the outside of the radiator shroud. So now I'm thinking top hose is the culprit. It feels less firm when squeezed than I would expect. (no "that's what she said" jokes please)

Net of this is I will order the top hose and replace. Can't hurt and may just cure it. I will also replace the bypass hose from the thermostat tower as it has the common "bulge" syndrome.

Should I stay with current OEM clamps or replace these as well?

 

Well done- I hope that's it. Will check there first myself shortly. Whenever changing out hoses, I always fit new screw-head type clamps. Good indicator going forward of what you've already done as well. You can get a package of them when you take the tester back to AZ!

 

OEM spring clamps are fine w/ new hoses. On old hose reinstallation if I cannot get the exact same position of spring clamp into the depression fit, I will use a screw type Jubilee clamp to give me an extra bit of tightening grip. When in doubt I always go for the screw type jubilee clamps. g.