Coolant leak advice

Hi all,

I recently purchased a new to me 2006 Toyota tundra v8 4x4 double cab with 200k miles and I am noticing a significant coolant leak.

It looks like the coolant is pooling up on the oil pan and maybe coming from the back of the motor.

I am not seeing any obvious leak from the hoses. Was curious if anyone else has had experience with a leak like this and could point me in the right direction.

I am worried it could be the head gasket, but the truck runs and drives fun. No funny smell or white film under the oil cap.

 

You sure it's coolant? i.e. it's red in color, not amber/garnet, and not brown? In that last pic, the oil filter housing has a cooling line that goes through it. But it also has a rubber gasket right up here that often goes bad and leaks oil out, from bolts above the oil filter housing. I can share a video. These trucks w/V8 are pretty well known for the valve cover gaskets leaking down onto everything also. The fact I'm seeing a fresh drip coming off the oil pan bolt in that last picture tells me it's above that - and I highly, seriously doubt it's the oil pan leaking unless someone had it off and didn't reinstall right.

Power steering pump and water pump are on the passenger side; only things with coolant on drivers side that immediately come to mind OTHER than the obvious radiator hoses, throttle body coolant passage, is the the radiator - this COULD be the radiator, but like other members found, it's only spraying water if you get someone to rev to 2k-3k RPM at idle while you watch for leaks from underneath. Also, note the radiator also has transmission lines going thru the bottom of it, which is why I ask, very clearly: Are you sure this isn't oil, i.e. motor oil or trans oil? You're 100% positive it's coolant?

If you don't want to invest the time checking these things, get a pack of shop rags, clean all this shit up, then run the engine and see where the oil is coming from. The fact I'm

 

I am pretty confident it is coolant. Doesn't have the consistency of oil. I have attached a clip of the leak happening below. It's hard to see, but it has a red tint to it.

 

Your likely answer is in this all-you-should-know thread in the "Recalls, TSBs, and annoyance" area, in the "coolant leaks" bullet point - you should probably read the 1st couple replies in that thread, as a new owner...:

• Coolant leaks: Three common causes: One is the is the gasket behind the thermostat housing, another is the coolant crossover at the rear of the block, and last but not least, old radiators is another source. Here's a list of things to check if you're losing coolant. For repairing the leak behind the t-stat housing, check this out. For the coolant crossover tube issue, you'll likely find coolant at back of the block, near where the trans and engine meet, check this reply for video/fix. For radiator leaks, this is one example of a tiny one - always replace with Denso brand, and know different cab types use different sizes. Proactive radiator replacement is smart. The transmission line routes through the bottom of the radiator, go look up "pink milkshake", it happens in these trucks.

The part I bolded specifically - that's what I'm talking about. IT'S SEMI-HIDDEN, so look carefully.

But seriously ... check that thread. There's probably a lot of stuff in there you don't know but probably should.

PS - If it doesn't say in one of those links, 10mm will let you pull back the passenger side timing cover, and you can shine a flashlight in to (A) check the condition of the timing belt, and (B) potentially see if the water originates back there (i.e. water pump). Alternately, look up from below to see if you see water coming out below or above either timing cover.

 

Also check the water pump for a leak and the weep hole under the input shaft. If your timing belt hasn’t been recently changed may want to do that and water pump

 

Really hard to tell anything from this video. Wipe the leaking fluid on a white napkin and take a picture of it for us. I really doubt it's your head gasket.

 

I just had the water pump and timing belt changed. I didn’t see anything leaking from there, but perhaps I missed it and it’s from the water pump.

I am going to have my mechanic look at it next week. Hopefully that is the case.

 

How recently? Looking at the video, that’s a very consistent leak in front of the oil pan. My guess is the water pump wasn’t sealed properly.

 

It was just a couple days ago recently. Hopefully you are right.

 

How much coolant have you lost?

 

So I’ve only had the truck a few weeks. The coolant was low before water pump was changed, but it apparently had a bad radiator cap.

Got the water pump and timing belt done. Only drove probably less than 30 miles, but mechanic noticed the leak after job was done and mentioned it to me. Reservoir has lost about half of coolant in those few miles.

 

Was the coolant low in the radiator or the overflow tank prior to the water pump job?

 

The water pump gasket tends to seal pretty well. I wonder if the tech didn’t seat the thermostat housing properly and it’s leaking down the front of the block. See here:

 

This is my guess as well!

 

Thanks everyone. I’ll check that out!

 

Late to the party, but did you ever figure out the cause of the leak? Your pictures look exactly like what I'm dealing with.

 

I wonder if he used the proper gasket maker on that thermostat housing or if the oring that slides into the engine got kinked or worse. He didn’t replace it! I’d replace the coolant hoses while your in there

 

Search this page for the word "coolant": https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

That will link to all the common coolant leak causes, most of them with pictures and fixes for the leaks in question.