Coolant Leak (1 Viewer)

[bj70alex]

Hi - I have a 97 LX450 with 196k on it. Recently, I noticed that I am loosing coolant. Rented the coolant pressure tester. Pumped to 20psi and noticed that an indicator dropping slowly. I checked for leaks and I saw the coolant coming somewhere from the back of the engine. Double checked PHH and it looks good (replaced it at 160k). Engine idles and runs great, no white smoke at all. Any ideas, suggestions, where that leak could by coming from, HG, heater hoses or???

Thanks,
Alex

 

[scottryana]

Alex,

This literally just happened to me yesterday. Mine went from no signs of leaking to large puddles all at once. It is amazing how consistent these failures are on these trucks. ha.

I think most people will tell you it is the heater control valve or rear heater lines. Best thing you can do is get a flashlight get in the engine bay, under the truck, etc and look for the leak while under pressure. Good luck!

 

[CJF]

HG...

We have seen a few external failures at the back of the engine. Go back and look.

 

[bj70alex]

Well, I hope that it's not an external leak from HG and I am going to replace No.1 by-pass hose. Now the question, how difficult is to perform that procedure? Any suggestions, recommendations would be appreciated.

 

[MoGas]

A flashlight and mirror will do you well. I'm thinking HG.

 

[IdahoDoug]

That hose is a tough one if you are speaking of the vertical one under the intake manifold. Easy during a HG replacement tho.....

DougM

 

[bj70alex]

That hose is a tough one if you are speaking of the vertical one under the intake manifold. Easy during a HG replacement tho.....

DougM

Doug - do I have to completely remove intake manifold or the plenum??

 

[CJF]

Well, I hope that it's not an external leak from HG and I am going to replace No.1 by-pass hose.

Without verifying that's the problem?

WTF?

 

[bj70alex]

Without verifying that's the problem?

WTF?

I will try to find the leak and see where it's coming from.

 

[bj70alex]

We have seen a few external failures at the back of the engine. Go back and look.

Hey CJF. We put some pressure on it and finally got it to start leaking enough to find a drip.

Trouble is, where it's leaking is the bottom, far-right (between 5 & 6) bridge of the intake manifold, to the left of whatever bypass hose that exits the block is.

I'm looking and looking and it just doesnt appear to be coming from above that point.

???

A flashlight and mirror will do you well.

lol...

 

[balcc9481]

I'm only a half banana mechanic, but isn't that area right below the return from the rear heater lines, and the valve for the front heat? Just did the bypass for my son's rear heater, and - I think - the area highlighted in the pic, is right below a bunch of little heater hoses and is prone to leaks either through rotted lines, or the heater valve adjuster thingy on the firewall. Were you able to isolate it yet?

 

[elhombre]

You said you double checked the phh, it sure looks like it is leaking there. Did you tighten up the clamps some? I know I have a problem when it gets real cold with those clamps because they seem to be extra sensitive to low temperatures. It took a few cold snaps to finally get them tight enough to not leak.

 

[bj70alex]

Update - I tried to tighten both clamps and as soon as I did that, did a pressure test again. Coolant was leaking from the bottom clamp. I used a mirror and discovered my own mistake replacing PHH a couple of years ago. I didn't install the clamp correctly. Loosened the clamps, repositioned the bottom clamp and the problem was solved. Thanks God, it was't the external leak from HG. Thanks everyone!!