2005 Limited v8, 162k miles

I was changing my oil last week and noticed coolant running down the side of the engine just on the inside of the AC compressor. I couldn't tell exactly where the coolant was leaking from because there was so much in the way, but my guess was that it was a hose, as I had to replace one of the coolant hoses that attaches to the oil cooler about 6 months ago. The reservoir was about halfway between the full and empty lines so I caught it pretty quick. I was already scheduled to take it in last weekend for an alignment and tire rotation so I went ahead and had firestone do a coolant system check as well.

They said they found that the driver's side head gasket was leaking coolant, but that they tested both the oil and the coolant and there were no signs of cross contamination. I'm aware that head gasket failure is VERY rare for the 2UZ-FE, and from what I'm reading, its even more rare for a head gasket failure to lead to coolant leaking to the outside ONLY. The car has also never been overheated, at least since I've had it. I kept a very close eye on it when the hose was leaking before and kept the coolant topped off at all times. Never once seen the temperature gauge go above halfway, never once had a check engine light.

I was fully preparing to buy all of the gaskets and take on the job myself next weekend, and figured I would replace the water pump and timing belt while i'm there since I can't afford a $3500 repair right now and I'll need a new timing belt in ~30k miles anyway. I'm pretty mechanically inclined, but this would definitely be the most complex engine job I've attempted- I just want to be damn sure that it needs to be done before I decide to tear the engine apart. Is there a more likely location near the AC compressor that I should check first? The photo attached is the best I could get of the coolant- I just cant see exactly where it's coming from. Photo is looking up at the red stain from right next to the oil filter.

Thanks in advance for any suggestions.

Attached Images

coolant leak.pdf (972.4 KB, 360 views)

I did a head gasket replacement about 55 years ago on an English made Austin 850 4-cylinder. I was a kid and knew next to nothing about how to do it and didn't get much help from anyone. I blew out 3 gaskets before I got it to finally stop leaking antifreeze into the cylinders and making the car look like a steam engine going down the road.

It is something I would not attempt again, and I know a lot more know and have better/more tools. Engines are so much more complex these days. You need a tool for just about every part of it. You sound positive on replacing the timing belt and water pump so maybe the head gasket wouldn't be too bad. Take videos of every area before you start so you have a reference point.

Have you checked some good independent garages? I think the cost is high and I would shop around to other garages that have excellent reputations. I would expect it to be around $2500 but the economy is unreal these days.

I'll plan on getting another quote or two tomorrow, $3500 is probably on the higher end but either way its more than I want to pay right now.

For something like this I'd certainly do my homework and order a full gasket kit and most of the hoses i'll be removing, just in case I break something in the process of taking it off. Engine bay is ridiculously dirty from offroading so it would be nice to get in there and clean things off too. Obviously I'd prefer not to do this repair but If im going to I want to make it worth my while and get some other stuff replaced while I'm at it.

I'm still just not fully convinced its the head gasket, I don't think the firestone diagnosis from a $32 coolant system check are to be 100% trusted.

I read this similar post on another 2UZ-FE coolant leak: 2uz Coolant Leak Help
The first response mentions that coolant often leaks from the water pump weep hole to the AC compressor side of the engine. This seems like it might check out.

I can't help you on where the leak is coming from...just wanted to reply about a leaking water pump on the V8, there's another member here who replaced his timing belt a few years back but didn't replace the water pump, his water pump started leaking and he either didn't think it was serious or didn't know it was leaking, I can't remember which, but anyway I believe it was about 30,000 miles after he replaced the timing belt the leaking coolant deteriorated the timing belt so badly it broke and unfortunately these V8s 99.9% of the time don't survive a timing belt breaking, he had to replace the engine, so if your water pump is leaking it's good you're thinking about doing the timing belt.

I also agree I wouldn't put much faith in Firestone's diagnosis, but you do have a substantial leak, I wouldn't think it would that hard to find where it's leaking, I would try and clean that area up somehow and see if the leak is more visible, get yourself a mechanic's telescoping mirror and a good flashlight to try and get a better view of where the leak is, you can get the mirror at Home Depot, Lowe's or any auto parts store for around $8 to $15, It would also be good to get a coolant system pressure tester so you can pressurize the coolant system so you don't have to start the engine to get it to leak, it a lot easier to find leaks without all the air blowing around frond the fan, and also safer to stick the mirror into tight spots, you might be able to rent or borrow a pressure tester from most any good auto parts store.

definitely going to do the timing belt while i’m in there, considering i’ll have to do it in 30k miles anyways.

I just got in there and got a better view of the issue from inside my wheel well, and indeed it does look like it’s coming from the front corner of the head gasket just under the exhaust manifold. Unfortunately.


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Likely a leaking water pump, the weep hole/duct drains off along that side of the block above the A/C compressor.

Looks like the source is above the gasket. No cross contamination is a good thing! To feel good check compression with free rental tools.

Do you think it could still be the water pump? the photo in my previous response seems to show it coming from just under the exhaust manifold connection. But as i look closer I’m noticing what looks to be dried coolant on the front side of the block indicating it dripped down and around to where the more apparent red stain is. Would this correspond with a leak from the water pump weep hole?

Also, I read your timing belt replacement write up from awhile back- I’ll definitely use this when i do mine here soon, so thanks for taking the time to do that.




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If you (or anyone) can give this one last look before I order parts it would be VERY much appreciated.

Where exactly is this weep hole? I’m picturing coolant oozing up and out of the seal between the block and the water pump, and I’m not seeing how it could soak all the areas that look wet in the photo attached. Am I looking at this wrong? The block looks to be higher than the edge of the water pump by about 1/8” so I don’t see how the coolant could run down and around the top/side of the block like it looks in the photo.



Looking online the only info I could find for the weep hole seems to point to below this area where I circled blue. It looks like there was some leaking down here at some point but I can’t tell how recent. I’m just seeing what is wet while these photos were taken-after driving home from work today. and I’m not sure how the water pump could cause it.



I guess I should plan for the worst, get everything I need for a water pump, head gasket, timing belt job and hopefully just have to do the water pump and timing belt?


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There's 3 main points that the pump can leak from that match roughly what you're talking about above the weep hole duct.

The first is the crossover tube O-Ring on the back of the pump that sits just above the front deck of the engine block between the heads, the second is also an O-Ring for the thermostat housing. The third is the water pump inlet/thermostat housing where you apply the FIPG. Those are all high enough to drain along the head gasket seam and are often where people who replace water pumps **** up the most. Either because they don't replace the O-Ring, don't lube it when installing it resulting in a tear, and/or don't clean the inlet properly before applying FIPG.





Some pictures I found on ih8mud that show what I'm talking about.

These pictures from MUD are great and helped me diagnose my leak. I also thought head gasket on my 2UZ but it was in fact a leaking water pump. I had that and the timing belt replaced (for an arm and a leg at the dealership) about 3k miles ago and have had zero leaks since, and zero coolant loss.

If you're okay with tackling the headgasket, then I would just go ahead with the timing belt/water pump first and then see if that fixes it. I imagine once you're in there you might find the remnants of coolant coming from the pump.

These V8s are interference engines. The valves, when opened, enter the cylinder where the piston will be. That's why it's so important to change the timing belt at the recommended service level. Any time you change the timing belt you change the water pump too, since you're in there anyway; cheap insurance. If the timing belt fails the pistons slam into the valves, a very costly repair. I wish Toyota had stayed with non-interference. Belt breaks you're stopped, but the engine is okay.

Ahhh I see it now. Thank you for clarifying, was going crazy yesterday trying to decide what to do but at this point I really just need to get everything I MIGHT need, start pulling parts off of it and see whats actually happening.

I went ahead and ordered:
Aisin WP/ TB kit
coolant
denso radiator (just because mine is beat and has green universal coolant mixed in)
thermostat and thermostat seal
crankshaft seal
drive belt
FIPG

If I get in there and don't see signs of leakage from the pump, I'll go ahead and order the head gasket kit and take the girlfriends car to work for the next week while I work on it. Hopefully it becomes more clear that its just a WP.

I'll update on my findings.

I wouldn't say I'm 'ok' with doing the head gasket. But I'm up for a challenge and think I'd pull it off if I take my time. WP and TB will get done regardless, I'm taking the advice to do that first and see what other signs of leakage are there after I take some more parts off.

Update--

Discovered the source of the problem to be the waterpump connection to the thermostat. Whoever did it last didn't bother to remove the old gasket material.. There were two different colors of FIPG as well as a paper gasket in there... lots of crusty red coolant on the back side that I wish I saw earlier. They also decided to put FIPG on both of the o-rings! AND the water pump gasket! This made it extremely painful to get off. I spent probably two hours scraping old crusty FIPG from all of those connections.

Still went ahead with the TB and water pump replacement- was not too bad, just need to finish up assembling a few more parts tonight and I'll be on to the transmission flush and replacing some work suspension parts. Thanks @BlackWorksInc - you were right about the water pump. Didn't see it before but now its clear after taking the thing off.