Coolant Levels Dropping Slowly - No Visible Leaks

[evsteroo]

I recently replaced all of the coolant hoses and the thermostat housing on my LR3. Coolant was seeping at various hose joints and through the plastic housing beforehand, now I can't find a single drop anywhere or any evidence of a leak and I am literally checking on a daily basis at every single new connection that I made.

Nevertheless, I seem to be losing about 1/8" to 1/4" in the level at the reservoir each time I drive, depending on how many miles I drive. The temperature gauge has stayed dead in the center of the range on the dashboard. I was very thorough in completing the full bleed process 4 times.

Is it normal for a very small amount of air to continue to be purged each time I drive for a few miles/weeks after introducing air into the system?

Thanks

-Evan

 

[ggrupea]

Hi Evan, I had the same issue last year, and the cause was the cap of the reservoir.

If this is not the problem, you could try to put some dust o something similar on every joint and get out and drive for some miles. Then check if one of those places have some marks of water passing.

Hope this help you, tell us if you find the issue to have it as a new checkpoint.

 

[evsteroo]

Thanks for the reply Gonzalo! I'll keep monitoring it for now, to make sure it doesn't level out and stop dropping, then give the cap a shot. I will update here if I find another reason for it, for sure.

 

[LVDaytripper]

Also, check the weep hole in the underside of the water pump. It could leak very slowly from that location and travel to nooks and crannies that you won't see. If there are signs of coolant coming from weep hole, time to replace water pump.

 

[anglotron]

There’s a coolant hose under the inlet manifold that can leak coolant and it can pool on the top of the block. It can also get into the oil and I had elevated levels of silicates when I had an oil analysis done at the time.

 

[evsteroo]

Anglotron, I have actually just replaced all the hoses, including that one (actually posted a guide on how I did it without removing the intake manifold in the other forum), and I check the area just above that hose from each and every time I drive now, seems bone dry. Nevertheless, it is a brand new hose, and I verified it was full seated before reinstalling the throttle body, etc. Thanks so much for the tip, though!

LVDaytripper, I will keep an eye on the underside of the water pump. Thanks!

Fingers crossed, the last time I check the coolant level it hadn't moved at all since my last top off (which was only to pour about 1/8" of level into the reservoir). Also, to be fair, I have less than 200 miles on my car since I did the work on the coolant hoses. It is possible I jumped the gun on getting worried about seeing rock-steady coolant levels.

In any case, I appreciate the input guys!

 

[Chris Moffitt]

If you have rear climate control there’s 2 hoses that are just above the spare tire

 

[bbyer]

Also, check the weep hole in the underside of the water pump. It could leak very slowly from that location and travel to nooks and crannies that you won't see. If there are signs of coolant coming from weep hole, time to replace water pump.

I recall that my Buick Roadmaster with the 5.7 V8 coolant level was slowly dropping but only rarely would I see any drips on the garage floor, and when I did, it was somewhat under the water pump area.

Ultimately it turned out to be the water pump leaking at the front seal but for it to actually drip out when parked, the shaft had to stop at a particularly orientation. When driving, fluid would seep out under pressure but also evaporate due to being hot and air movement.

I routinely put that blue UV dye into my AC system when recharging. I presume the same can be done re engine coolant.

If you had coolant leaking into the engine, I think you would see foam on the engine oil dipstick, (if the engine still has one).

The odds are the problem is the water pump but could be a hose or the pipes leading to the rear heater as well - those are pretty much hidden.

 

[NorthwestDriver]

Fingers crossed, the last time I check the coolant level it hadn't moved at all since my last top off (which was only to pour about 1/8" of level into the reservoir). Also, to be fair, I have less than 200 miles on my car since I did the work on the coolant hoses. It is possible I jumped the gun on getting worried about seeing rock-steady coolant levels.

In any case, I appreciate the input guys!

Sounds like you were working air out of the block, hoses, and radiator each time you took a drive. I recently did my F150 cooling system (all hoses, pump, thermostat, etc) and I had to add about 2 quarts of coolant after initial fill. This was over 3 cycles of getting the engine up to temp. My truck doesn’t have an air bleed valve, whereas I think the Land Rover does.

 

[evsteroo]

NorthwestDriver, that's similar to what I was initially thinking might be happening. I did bleed the system properly three times right after I did the job, where large volumes of air "belched" out of the reservoir, but it seems to me that in such a labyrinthine system, small pockets of air might migrate to the reservoir much more slowly than the bulk.

Bbyer, thanks for the input, I'm just keeping an eye on the reservoir levels and doing my best to inspect the water pump and the visible portions of the rear heater lines on a regular basis (after just about every time I drive the LR3).

The last time I checked the level it had barely moved. Fingers crossed, I do think the level is getting more stable. I am, admittedly, extremely fussy when it comes to noises, fluid level changes, etc. So maybe it was nothing to worry over.