LMM: 08 LMM 3500DRW (HELP) Losing Coolant BAD!

[wkachnik]

2008 LMM 3500DRW - 160K miles

We are losing coolant (lots) - know exactly where it's coming out of - the pressure relief valve at the bottom of the coolant reservoir.

Mainly we'll drive it - park it for a couple hours - come back to a big puddle under the passenger front. Has been getting steadily worse the last 2 months.

Even with the engine off - parked - when we squeeze the upper rad hose on the drivers side that's enough to make coolant stream out of the pressure relief valve on the bottom of the tank.

Just in the last week have started getting messages about low coolant - each time reservoir is essentially empty.

Tried smelling the oil dipstick - just smells like burnt oil. Can't for the life of me see any bubbles in the lines or tank. Waiting to let it cool a few hours to check on if the rad hoses get hard.

Thoughts?! We just bought this truck used in November - wife is freaking out

 

[PACougar]

You have a blown head gasket!

 

[wkachnik]

You have a blown head gasket!

How would we know for sure? Talking w/local mechanics they claim it's rare for LMMs - and we want to know for sure before undertaking such a HUGe deal....

 

[PACougar]

You've literally described every classic condition that happens with a blown head gasket. I've had it happen and you could be describing my truck and many others in your first post to a T!

 

[wkachnik]

So we need to drive it... any thoughts on how long it will be OK? Anything we should do in the meantime to minimize more damage? Or, will it even hurt it more?

 

[PACougar]

I drove mine for 3 months, I certainly can't tell you nothing else could get damaged. Make sure not to let the coolant level get low, you don't want a blown motor.

 

[coker6303]

You sure the valve is holding enough pressure back? Maybe it's weak and opening too soon?

Just throwing a scenario out there.

 

[wkachnik]

You sure the valve is holding enough pressure back? Maybe it's weak and opening too soon?

Just throwing a scenario out there.

That is/was my initial thought! My wife got on these forums though and after reading all the posts like PAC's that it has to be the HG I gave up on the thought process.

BUT - it's weird to me that even when it's sitting (no pressure) and I use my hands to massage the upper Rad hose and it starts leaking all over too...

Assuming only way to 'fix/replace' the valve is to replace the entire reservoir? (which is easy)

 

[coker6303]

So when you squeeze the driver side hose, is it soft? And as it compresses you hear the coolant/air pass at the valve?

 

[coker6303]

I have a LMM coolant reservoir in my attic...cheap! :thumb: unless you can get the valve, that would be easier. I haven't even looked at one

 

[wkachnik]

So when you squeeze the driver side hose, is it soft? And as it compresses you hear the coolant/air pass at the valve?

So far the hose has been soft, yes. BUT - been letting it sit for 3 hours will go out soon and check on it to see if getting hard(er).

For the "valve" do you mean the pressure relief at the bottom of the reservoir that it's leaking from? If so, don't notice any sounds... might try and listen again though...

 

[coker6303]

By sounds I mean you can hear the coolamt/air pass the valve when you squeeze the hose?

If you can light squeeze the hose and coolant pisses outbof the valve, the valve is crap. They hold back like 16-18psi I think. Pretty stout squeeze if you are pushing that from the driver side hose!

 

[wkachnik]

By sounds I mean you can hear the coolamt/air pass the valve when you squeeze the hose?

If you can light squeeze the hose and coolant pisses outbof the valve, the valve is crap. They hold back like 16-18psi I think. Pretty stout squeeze if you are pushing that from the driver side hose!

Just went out and checked the truck... been sitting/cooling for 3.5hours and the hoses are SOFT. But, the damn valve is still slightly dripping coolant just sitting there. Opened up the cap (NO pressure).

 

[PACougar]

Well, that's great to hear. If the hose is soft and the valve is still leaking then it sounds like a easy fix.

 

[wkachnik]

Well, that's great to hear. If the hose is soft and the valve is still leaking then it sounds like a easy fix.

From your words the truck working HOPING we don't fix the damn valve and then the hoses start getting hard because the new valve starts letting the pressure build up

 

[PACougar]

Me too! Good luck.

 

[wkachnik]

WOW - well just bought a new reservoir tank and it's COMPLETELY different from the one that's IN the truck now!

The one that's currently in truck DOES have a relief valve at the bottom of the tank that IS faulty. The new one DOES have the relief hose at the top/side of the tank like everyone has been describing.

Not sure where the current tank came from but will install this new one and see what happens...