I "rented" a tool from Advance Auto that lets me do a coolant pressure test for the 2003 Discovery that has about 86k miles. I was suspecting a small leak somewhere that I couldn't detect.

I got this coolant pressure test and I was able to get it up to 13 psi by pressuring up the expansion tank. I waited for a few minutes and it never dropped. Is the 13 psi high enough to pressure test the coolant system?

Thanks.

 

I'd think operating press (14-16psi) would be perfect.

It's not so much as how much pressure it can stand (don't blow out the seals), as will it hold pressure for an hour.

13psi for an hour (understand if you start out hot & it cools, the pressure will drop)

Do it cold, then you can monitor 13-15psi for 20mins. or so

If it holds that, you're good

This is all depending on your press test tool being perfect (zero leakage), which is 50/50 chance.

luck,greg

 

I usually recommend 2 pounds over the normal operating pressure, 17 to 18#'s and as already mentioned give it some time.
Let us know what you find.

 

OK, guys. I finally got around tonight to redoing the coolant pressure test. My pressure tool is one of those kind that slip into the hole and you make it press fit into the hole. So, I'm having a hard time getting the pressure up to 17-18 psi. I was able to get it to hold for about 10 minutes tonight with me trying to keep my weight on it. I think it lost about 2 psi maybe? I wonder if it some of it came through the press fit tool?

Anyways, I tried to look for any external leaks afterwards (the press fit tool blew off and there is a little bit of coolant everywhere). But I think I may have a possible location for an external leak. I noticed that the hose that goes from the throttle body to the engine block may have leak right at the engine block. I found where some coolant has collected there and it could be somewhat fresh. However, about 4 or 5 months ago, I did have the gasket at the throttle body blow out and I replaced it back then. Is it possible that this is just old coolant? I figured by now it probably would have burned off from all the engine heat. So, I suspect that is more fresh coolant and that it is leaking from the hose clamp area at the engine block. I didn't notice a trail of coolant though.

Any suggestions on how I can double check on this being the source of my coolant leak?

 

When you get a proper tester run it up to around 17#s for 15 to 20 minutes, then get back to us.

 

Alright...did it again and I was able to see fluid leaking out of that hose from the engine block to the throttle body plate. It looks like I just need to replace that hose clamp with one of those kinds that can be screw tightened. Is there any easy way to get to it without having to take the belts off and removing the alternator and compressor?

 

You can buy pass the hose or order a up-dated gasket kit from Rover for around $28.

 

The throttle body heater plate is a VERY common leak and a $3 fix.
You can buy a new gasket at the dealer or from www.atlanticbritish.com.

 

Yeah, I've already replaced that throttle body plate and gasket 4 or 5 months ago. Where I saw the leak is coming from the short hose that goes from the throttle body plate to the engine block...the end that attaches to the engine block. Looks like all I need to do is replace that clamp with a screw style clamp and it may stop the leak coming out of that end of the hose. Hope this makes more sense with where I was trying to explain the leak.

Also, I spent a little bit more time looking over more potential leak areas. Is it possible for coolant to leak out of the gasket between the oil pan and the engine block? It looks like there is some coolant dripping down from that area (on the drivers side of the engine block). I suspect though that this may be coolant making its way down from that hose leak at the top of the engine block that I was referring to earlier. Let me know what you guys might think.

Thanks!!

 

There is no coolant flowing through the bottom of the engine, so no, coolant will not leak from the oil pan gasket.
Coolant flows around the cylinders and through the heads and thats it.