Rear heater coolant leak (at hose connection point to rear heater) - anyone have this happen?

[arbetrader]

Hello all, I have a 2008 LX570, and I have what appears to be a small leak (probably for a while now) - I removed the rear seat and inspected in behind the panel (Driver's side rear)

There is dried coolant on both hoses at the point that they connect to the rear heater box.

I'm afraid to pull the rear heater box because it looks very complicated and I don't want to risk breaking anything, that being said, has anyone had this happen, and I'm wondering if anyone has had any cracks in the actual rear heater OR perhaps not? I don't use the 3rd row anymore so not sure I'd even need this, but regardless it would be nice to stop this leak

Should I start by just replacing the hoses and new clamps?

 

[bloc]

I’ve seen a few people post with leaks under the vehicle where the hoses run through the floor, but can’t recall one in your problem spot.

The hoses would be a relatively simple and cheap first step, but my gut is they won’t get you very far.. the rubber parts I can see don’t have any swelling or degradation that rubber coolant hoses usually have before failure.

Worst case you could bypass the core back there if it won’t get used.

 

[CanadianRockyCruiser]

Have you ever changed the coolant? Any known history of overheating due to coolant loss elsewhere in the system? I'm thinking this might have been caused by an event of overheating/increased system pressure. It might be worth examining the other coolant system weak points; the water pump, the valley plate, overflow reservoir, and the radiator itself for any indication of similar leaks.

 

[Sandroad]

Use a toothbrush and clean up the clamp on the right. It looks oddly corroded, but it could just be dried coolant. If it’s bad, it would cause the leak.

 

[arbetrader]

So I ended up removing the old hoses and installed some new ones. I also used new clamps. These were a bit hard to remove given the location... Took a few hours to complete given I had to remove so much other stuff to simply get to them. It was a pain.

Anyway, hoping it holds better now. Will monitor and update if any further issues.

 

[linuxgod]

Wondering how you knew to look for a leak. Coolant level dropping? If so by how much and how often were you topping it off?

 

[unclemat]

I also have a very slow coolant disappearance visible in the overflow tank. Going to inspect the valley plate but that looks another spot to inspect.

As a side note it seems a lot of coolant stays around during replacement, did not think about the rear heater. I never tried vacuum purge on the Cruiser, as it sometimes can cause grief. Anyway I am on 50k/5y coolant replacement schedule so some old coolant left behind prolly is ok.

 

[Valgrind]

Sorry can you explain a little more where this is?

 

[linuxgod]

I also have a very slow coolant disappearance visible in the overflow tank. Going to inspect the valley plate but that looks another spot to inspect.

As a side note it seems a lot of coolant stays around during replacement, did not think about the rear heater. I never tried vacuum purge on the Cruiser, as it sometimes can cause grief. Anyway I am on 50k/5y coolant replacement schedule so some old coolant left behind prolly is ok.

My valley plate was done maybe 18 months ago. I’ve see my coolant at about 1/2 between L and F. Topped it off 800 miles ago, seemed to hold steady for 500-600 miles, then I checked the other day and it was around 1/3. Topped it back off, stayed at F a couple days, then yesterday was at about 120% (over F). Not sure if I shouldn’t have topped it off when it was between the marks? Seems off my loss isn’t linear, and at first I thought maybe an air bubble but now I’m wondering if it’s just expansion/contraction because temps have been single digits.

 

[PDoyle]

I’ve had the same senero. Seems normal.

 

[Fisher23]

So I ended up removing the old hoses and installed some new ones. I also used new clamps. These were a bit hard to remove given the location... Took a few hours to complete given I had to remove so much other stuff to simply get to them. It was a pain.

Anyway, hoping it holds better now. Will monitor and update if any further issues.

I take it you went looking as you were loosing coolant?

That sure looks like a very very small leak. Is it still leaking somewhere else?

 

[linuxgod]

I’ve had the same senero. Seems normal.

Yeah the FSM implies you should give zero f*cks unless it’s below L or above F when the engine is cold, according to the instructions on how to bleed the system. But that just feels so wrong to me. Maybe I’m pushing some coolant out the overflow though.

 

[PDoyle]

I've added coolant a few times when the tank was low, only to find it over full later on.
Side note, just happened to drop the overflow cap when checking and I think it fell and landed inside the skid.
New caps are $20. shipped. Part # 16405-50080

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[arbetrader]

No, mine is still losing coolant. I went to re-check the work I did on the rear heater, and I think it's still leaking. I think the rear metal inlet hoses are bent (were like that prior to me purchasing) so somebody monkeyed around with it previous to me getting it. Strange, as it was a one-owner, and always dealer serviced.

Anyway, I'm not 100% sure this is the only point of coolant loss. Perhaps it is... Might need to run a pressure check etc. I already changed the rad cap a few monthsa go (new). it's still going through a small amount of coolant, but not sure it's worth me fussing about at this time, given the fact that I just top it off once every week or two with a small amount (It's my wife's dd).

 

[arbetrader]

Wondering how you knew to look for a leak. Coolant level dropping? If so by how much and how often were you topping it off?

I was having a prior AHC issue, and the mechanic (at the time) removed the rear seat and pulled the panel off b/c there is an AHC computer back there (for diag purposes). That's where he noticed the leak. It looked like this