I've had a coolant leak for a little while and finally had the water pump replaced. Noticed today that it is still leaking. Outside of the tank, anyone know where the leak could be?

 

I assume you are seeing the leaking fluid (as opposed to just noticing a drop in fluid level).

From the front, the most insidious leak is the front coolant crossover. This can leak at the top part of the pipe (which you can see when looking at the engine) or more commonly at the bottom of the pipe where it enters the block (which you cannot see). Sometimes the fluid just sits in the valley, and other times it spills out the front and can leak behind the pump (so it looks like it’s the pump leaking). Take a flashlight and look down into the valley of the engine (there’s a little space here and there around the oil filter). You might see some orange fluid. In any case, if you haven’t had your front crossover pipe replaced before, you should do it now and every 50K-75K miles. Many people have lost engines to this leak.

The other spot at the front that’s common is actually behind the water pump. There is a tube that goes straight out the back of the water pump and delivers coolant to the oil cooler. That pipe and the o-ring that seals it needs to be changed when you change the water pump (it’s a separate part too). And, when you’re putting it back, it’s really easy to get that pipe seated incorrectly. If it’s not changed with a new o-ring, or it’s not seated correctly, it will leak.

Another spot for leaks is at the back of the engine - the rear crossover. Can’t really see it as it’s down below the heads, but you can feel it. When this leaks, you’ll see it on the floor or skid plate at the rear of the engine. This should be changed when you’re doing your front crossovers. Not nearly as often a problem, but it is still a plastic pipe that degrades and has caused leaks on quite a few cars.

 

I should have been a little more clear actually. I am smelling the coolant and noticing a drop in the level in the tank. No puddle though. I had a mechanic do the water pump and he was to replace all associated hoses and that tube behind the pump. Also I just had the pump done about a week ago. Thanks for the info though. I'm going to start looking around for any leaks in those hoses and plan to take it back to the mechanic and plan to make him do it again for free if he failed to replace any of them.

 

If your not seeing the leak, then the front crossover is the prime suspect - leaking down into the valley. When the engine is hot, it dries up on the block, so some leaks go undetected until it just completely bursts. At that point, you’ll have just seconds to shut the engine down before overheating. Good luck with it.

 

I just had mine done. I was in Utah and was just heading out back to San Diego. Had a low coolant warning. Mechanic thought is was the water pump. He changed the water pump and some hoses and belts. It was still leaking. Turned out it was the front cross-over pipe. He ended up replacing the front cross-over and the rear heater hose manifold. That fixed the leak, and my wallet.........They forgot to completely tighten up the bleed screw on the rear hose going to the heater hose manifold. Tightened that up and all is good. I did have the coolant smell for a couple of weeks, even after several thorough, low-pressure engine compartment wash downs. Good luck. Phil

 

Yeah I checked the coolant level yesterday before getting groceries, and I went out and checked this afternoon. It actually hasn't moved. I do still smell it though. Gonna keep a close eye for the next few days before I call the mechanic enraged haha. Thanks Phil!

 

Hi there - i am in the same situation, replaced water pump and all associated hoses / pipes and still have a coolant leak. did you end up finding what was the culprit for yours?

 

Here are a couple of links to LandRover/Jaguar documents

This one concerns the water pump, and to check if it is faulty. There was an update made to the pump design at a certain stage

https://static.nhtsa.gov/odi/tsbs/20...04441-9340.pdf

This document relates to the Jaguar , but it is the same for coolant pipes on the 3.0 SC engine. You can see that they introduced a revised non jointed design for the front upper and lower coolant pipes (it is hard plastic) as there were leaks coming from the split in the old pipe design and also from where the pipe goes into the block. It is worth checking you have the latest design on those 2 pipes. The pipes cost very little, but you need to remove the supercharger to get to the lower pipe.

https://static.nhtsa.gov/odi/tsbs/20...42170-9999.pdf

 

General rule here: If your replacing the water pump you also replace the thermostat, and front and rear crossover pipes. These are well documented for having failures. The V8's are great as long as you keep them in great shape otherwise you have a boa anchor. Never do 1 without the others.

 

Same issue here. I had both cross over pipes replaced, the pump and some hoses a few months ago...then the radiator replaced a week later (because my indy assumed the leak was the cross over pipe. It was actually a punctured radiator. Wasn't super happy about that but I chalked up the cross over pipes as preventive maintenance. However...now I have slow leak somewhere. Cant find where. Im reluctant to bring it back to my indy because we didnt end on the best terms after they f'd up the last job

Any tips on where to look for the usual suspect places. I took the skid plate off today to try to see what I could find. I found some coolant on the lower hoses right about the front skid plate (dont know what those are), but unsure if that was dripping down from above somewhere.