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V6 Camry leaking coolant heavily on passenger side

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4.1K views 21 replies 3 participants last post by  stokesy  
#1 · (Edited)
So I've got a coolant leak on the passenger side of my V6 engine. I suspect it's either the water pump or that darn coolant bypass hose. But I cannot see the source of the leak. Coolant is dripping rapidly off the oil drain bolt. Symptom is coolant boils in the overflow tank. Perhaps even a head gasket blew out catastrophically?

Thanks for help
 
#2 ·
Does it leak when the engine is cold and off when you fill it?
Does it leak the moment you start it up or only when it gets warmed up?
Is it over heating before it leaks?
Check your oil, does it look normal or like chocolate milk?
Any work done on the car recently?
Did your engine experience an overheating event just before you noticed the leak?


The water pump is a possibility, it would leak on that side of the engine. I am assuming you have a bracket and timing belt cover that blocks the view to your Water pump? If it is anything like my lexus, it is a bch to get to the water pump just to be able to visually inspect it and even more of a pain to replace it. If you are lucky you might just have a bad thermostat causing overheating and coolant res overflow. The Thermostat is much easier to get to and replace. Do you know when the water pump was last replaced? If it has a timing belt that runs the water pump it was likely replaced when the belt was last replaced, usuallly a good tech will put a sticker with the date and mileage on the timing belt cover when it was last replaced.
 
#3 ·
good advice. I will fill it up again and see when it starts leaking. The timing belt was done recently but the tech said the water pump looked ok:(. my friend drove the car hard on mountain roads on the hottest day of the year. He melted the coolant reservoir cap and overheated the engine. Luckily the ECU for this car starts dumping fuel and stalling the engine when it overheats(y)

and yeah the timing belt and water pump access is pretty tight. I'm used to working on Acuras which are also a snug fit. But I really don't wanna waste effort on the wrong job
 
#4 ·
They should have replaced the Water pump. It is pretty standard that due to the difficulty to get to these items that when you do a timing belt replacement you also replace the water pump, belt tensioner, Idler pulley, Tensioner idler pulley and the Cams and Crank oil seals. You can get all these items together in a kit. If your pump is bad now all that has to be opened back up, the timing belt has to be removed, recompress the tensioner or get a new one. Then put all that back together again, Like doing the timing job twice.

If the engine was ran overheated and got low on coolant, that is a recipe for a head gasket failure. You are going to have to find a way to trace exactly where the water is coming from. Jack the car up and get under it, use a automotive mirror tool etc. you can also look at that side of the engine from the wheel well, turn the tire all the way to the right and there may be a plastic part that can come off easily for access to the crank shaft, will give you some more area to view to find the leak. If the water pump is leaking, you should see it flowing down that side of the engine from out under and to the left/Rear of the bottom timing belt cover. If it is the res I would think it would leak down the side of the engine bay not down the engine itself unless it is leaking from the radiator cap area where the over flow tube plugs in, Make sure that is attached. Leaky upper hose can cause coolant to come down the side of the engine as well but should be obvious.
 
#7 ·
Thanks for the replies everyone. I stuck a borescope under the intake manifold yesterday. I couldn't see much, but will review the videos tonight and post if they are relevant. I did see the characteristic pink and orange colors.

Also, I refilled the filler neck with water and observed it draining out with a cold engine that was turned OFF.
 
#9 · (Edited)
I pulled the passenger wheel arch and didn't see any leaking on the timing belt cover. It's dry so the coolant is leaking from behind that cover, but I'm not sure if it's the water pump or maybe that bypass hose. The oil looks clean so I don't think it's a blown head.

Here are a few captures from the Camry's valve coveroscopy. Hard to tell what I'm looking at but I think it's some sensor (knock?) and some corroded and wet parts. I will try again at night as I couldn't see what the scope was seeing, the outside light was too bright.

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#12 · (Edited)
I think your engine is much the same as mine, if so, the picture below shows where to look for coolant if it is the water pump failing, You should see it flowing down to where the large pink arrow is pointing, from there, depending on how heavy the leak is will flow down onto the frame under it and around the engine or just from there rearward and around the back of the engine and down the oil pan onto the ground. This is behind the passenger side wheel, you can remove the plastic cover infront of the crank pully to get a better look.
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The water pump is covered up pretty tight with the center bracket and the upper and lower timing belt covers, no place to sneak the snake cam in, but I think the easiest access would be to unclip and move over the wire harness clipped to the top of the rear side of the upper timing belt cover marked with the red arrow, then pull several of the bolts out of the top cover, do not try to remove it completely because you have to remove at least one bolt from the bottom and could break the cover at that spot. Just remove the top bolts and pull it back enough like the picture below to be able to get the snake cam in, You cant to get it down the space in the bracket right where the green arrow is, that is the pulley for the water pump and some bottom edge of the water pump, If you have a leak from the water pump you should see it dumping out there when you add the water. If the bottom cover is nice and snug the coolant may be pooling up a bit in there before leaking out from behind the crank pulley, getting coolant/water all over the crank shaft gear/washer/the sensor and all over your new belt itself, if so it may be flinging water up all over your idler pulleys and cam pulleys etc. while your cover is open a little like in the picture below, you can try starting it up after adding water, and it leaks a bit to see if the belt itself is wet. Your mechanic should have at least tried to talk you into a new water pump. Knowing it is basically a timing job to get to the water pump, and you would not be in there again for another 90K or more. Hopefully it is not the pump or head gasket.

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#14 ·
Just finished mine today, do not what to do that again any time soon. But I did it for $400 in all Quality OEM parts. The shop wanted something like $1300 to do it. I have better uses for that $900 saved. And I know exactly what parts are in it and that everything was done correct, everything properly torqued etc.
 
#16 ·
No, You can put in the pump without taking off the cams and backplate, but it is kind of a pain. IF your engine is just like mine. The backplate in metal, the water pump has a lip on the top edge that sits behind the backplate, about 1/4 inch. I have done it once when I could not get the cam bolts off. The water pump fit on with 3 nuts on the left side, a couple long bolts, there are also 2 threaded pegs, to get the water pump to slide off those pegs you have to pull it straight out, but you can not pull the pump straight out because the top of it fits under the lip of the backplate.

You will have to remove the nuts and bolts, then remove the 2 pegs, you can unscrew them with a small E-Torx femal star socket. Pull those two long pegs out. Now you can work the pump off with a little wriggling. Putting it back on is a bit harder, it does not just slip back on under as easy as it came off. I took out some of the bolts that hold the backplate on, this allowed me to be able to pull the bottom of the plate out just enough to force the lip of the water pump back under it, a little tricky but very doable, just be careful when forcing it in that you are not putting any pressure on the new metal gasket so as not to damage it. You may need to use a screwdriver or something like a needle nose plier with an angle at the end or something else that you can use to get behind the bottom lip of the back cover to pull it out to create space to fit the pump in.

So yes you can do it, but you will have to take out a few bolts from the backplate, Now this brings up another issue, the bolts are behind the cam pulleys. The pulleys have spokes with open spaces so no problem accessing the bolts, but if it is lined up like mine was where both bolts just happened to be lined up behind 2 of the spokes, then you have to turn the cam pulley maybe up to 10 or more degrees one way or the other to get your socket on it. Turning the cam even a little you run the risk of forcing a valve to hit a piston possibly and doing damage, The manual on my engine tells me to turn my crank shaft counterclockwise 60 degrees before messing with the cam pulleys such as trying to get the cam bolts out so if they move you do not damage anything. I would for safety go ahead and do the same, you will have to find the repair manual instructions for your engine, On mine, 60 degrees was exactly 2 teeth on the crank shaft. Then you can mess with the cam pulley. Just remember to get everything lined back up when you put your belt back on.

one more thing, with the back plate on, I could not fit the metal gasket back in place without risking damaging it due to one of the little pegs on the gasket, I had to cut the little peg off with a wire cutter then it fit on flat without any forcing.
 
#17 · (Edited)
Thanks, I had a feeling that was possible. I will try to pull those studs and sneak the pump on behind that rear TB cover after I loosen it up a bit.

I think a valve hitting a piston is only dangerous when the engine is running. I have broken timing belts several times on interference engines, even then I never had valve damage. But I have seen a photo of a bent valve stem.

I got an OEM water pump for $65

But I just had a terrible thought:
What if the tech who did the timing belt forgot to torque in the rear block coolant drain?! Will check it if I can find it.
 
#19 ·
I wonder if the mechanic that said the pump looks good, if he did anything to the pump, like pulled it off to inspct internally, if so, maybe he did not replace the gasket or forgot to torque something down on the pump. Once you have access you can then add water/coolant and see exactly where the leak is coming from, gasket or pulley, and check the torque on the nuts/bolts just for the hell of it to see if it is age or mechanic error.
Good luck.
 
#22 ·
thanks for checking on me. This job is getting weird: I took off the timing cover and pulleys and inspected the pump. Just to double check, I poured in water to the top of the filler neck and ran the engine for a minute. To my surprise, the pump didn't leak at all. I thought maybe it only leaks when the system is pressurized, so I revved up the car for a few minutes to heat it up. Coolant started leaking from the overflow tank. I think the coolant has been flowing all the way around the frame of the car and dripping down to the oil pan, making it look like the engine is leaking coolant.

I thought about it for awhile, and I think the thermostat is just stuck closed. And basically I haven't been able to fill the cooling system ever since it failed.