Passenger side rear cylinder, just above the starter.

I’ve had a slow coolant leak for a while. Couldn't figure it out, not enough showing around the water pump.

Dye kit led me to the back. Saw this.

The heater core hoses are above this, but they look solid.

The coolant is mixing with the slightly leaky valve cover gasket.

Any chance this ISNT a head gasket leak?

It’s very slow, is considering a Stop Leak solution for now a crazy idea, and monitor it?

I’ve been using small amount of coolant for over a year now.

 

I had a similar leak on the drivers side of my P38. It was an intake manifold bolt that wasn’t tightened properly. The problem with Stop Leak is that it can clog up your radiator and heater core. For a small leak like that I don’t think it’s worth using Stop Leak.

 

I would recommend running without pressure in the cooling system if you want to slow it down: https://landroverforums.com/forum/di...46/#post887409

 

Fascinating read. Thanks Extinct.

My temps have been low, since the bypass mod/lower stat, etc many years ago.

Temps run between 172-189 ish. There was one time last summer I was hitting 210-215 uphill. One event. Hated it.

I switched my coolant bottle a few months ago for a stainless one. https://carrs4x4.com/products/land-r...tank-reservoir

Is the 20psi cap higher pressure than stock? Did I increase pressure, swapping that?

I think I was losing a small amount before that tho.

I’m obviously worried about scoring a line through the block with coolant exiting at pressure through a small gap.

I’m at nearly 140k miles. Original HGs. So, it’s not insane it’s my time.

 

Stock is 1.4 (stamped on the reservoir cap) bar = 20.3psi.

 

Depends on the cap, there were two, 1.0 and 1.4. Does not matter which you run if you run loose but I definitely would not run the 1.4 cap.

 

Chatted to a local mechanic who works on my car when rarely needed. He suggests the leak is so slight to just monitor it.

I'm tempted to run the non pressurized idea. Which in theory could reduce the coolant loss.

I never get above 190 in the current pressurized system.

If the truck never reaches 228 deg, it will never boil. Evaporate, yes. But that's easy to monitor.

Can I just crack the top of the cap to unseal it, set an Ultragauge alarm for 200, and go about my day?

 

Yes, tighten the cap fully then back off one full turn. I have been running all my trucks like this for over four years.

 

So far, total success. Unpressurized for about 2 weeks. And no sign of those coolant drips on the block any more.

Extinct, you legend.

I'm nearly at 140k, wonder how long I can take these original HGs.

 

I didn't know that they are out there since that would be out of spec. Where could I get a 1.0 cap? I never seen that sellers specify relief pressure and, honestly, I never thought about it when buying one.