Thermostat gasket failure?

[DK327]

Hey all, while I was attempting an oil change, I noticed some dried pink stuff splashed all over around the thermostat housing, below is a pic, just need confirmation that it's probably due to thermostat gasket failure.

The only thing I can think of is that it's coolant and the fact that it's around the thermostat housing probably means it's the gasket... Upon further inspection, I also noticed my coolant level in reservoir was "low" meaning I've lost some although apparently not enough to cause a temp increase in Scangauge.

Anyway, I have 3 gallons of 50/50 toyota coolant and oem thermostat gasket on the way already; I had done this service about 16K miles ago, at which time I had replaced the OEM radiator with Koyorad A1998, thermostat (OEM), gasket (FelPro), upper and lower hoses (OEM) and the radiator cap (OEM) and it's been great until right now.

I guess this is why the FelPro brand gaskets are also referred to as "failpro" what a POS!

 

[Kanoe]

I guess this is why the FelPro brand gaskets are also referred to as "failpro" what a POS!

Some people seem to like FelPro but every single one I have used has come back out due to leaks within a couple of years. Never again for me, OEM only.

 

[DK327]

Some people seem to like FelPro but every single one I have used has come back out due to leaks within a couple of years. Never again for me, OEM only.

Right on, I don't know what I was thinking, getting everything OEM then a FelPro gasket... Oh well, at least I discovered it before taking a trip to the cabin next weekend, now just waiting on the OEM gasket and coolant to arrive so I can start slicing and dicing!

 

[sakoluvr]

I had a leak from my water intake housing but it was not that bad. I replaced the t stat after a radiator change and then noticed the leak. The housing had small pits that corroded near the gasket.

I used a Toyota t stat and gasket and had to buy a new water intake. I quickly realized how smooth and polished a new water intake was. That FIXED the leak. Looking at yours it looks more like the gasket. I was just getting a steady slow drip.

Don't forget to torque down evenly with 14 ft lbs. I had to replace a couple of studs too. Jiggle valve at 6:00.

 

[thegipper]

I had a leak from my water intake housing but it was not that bad. I replaced the t stat after a radiator change and then noticed the leak. The housing had small pits that corroded near the gasket.

I used a Toyota t stat and gasket and had to buy a new water intake. I quickly realized how smooth and polished a new water intake was. That FIXED the leak. Looking at yours it looks more like the gasket. I was just getting a steady slow drip.

Don't forget to torque down evenly with 14 ft lbs. I had to replace a couple of studs too. Jiggle valve at 6:00.

This.

Often times the housing itself is pitted/corroded and even with a new OEM gasket, it will leak. Generally that is a sign that the coolant wasn't replaced often enough and caused the corrosion.

Mine was corroded so bad on my old motor that it almost had holes through the housing.

 

[DK327]

This.

Often times the housing itself is pitted/corroded and even with a new OEM gasket, it will leak. Generally that is a sign that the coolant wasn't replaced often enough and caused the corrosion.

Mine was corroded so bad on my old motor that it almost had holes through the housing.

Thanks, when I take it apart i’ll check the housing and clean it thoroughly if needed. The fact that it was rock solid for 2 years and 16K mikes I think its just the gasket that gave up, but I’ll definitely verify the integrity of housing.

 

[Sonny.Deez]

Hey everyone, sorry I know this is an old thread but I’m having a problem that may be similar to what was described in this thread.

I have a bad coolant leak, soon as I put in fluid it starts dripping/pissing out. Started slow but couldn’t find where it was coming from till I finally took it to a friends shop yesterday.

I found the leak, but I have no idea how to fix it. I initially thought it was leaking from the thermostat housing.. If you’re looking into the engine compartment from the front of the truck, the leak is to the left of the thermostat housing. I will attach pics, but after I took of the timing belt cover, I could see a “channel” of some sort (not sure if channel is the right word) that leads to a “lip” where the water drips out of. I will attach pics with the channel and lip circled. If anybody knows what this is and what the solution may be, I would greatly appreciate it. I blew into the overflow hose to pressurize the system, and there was definitely a leak coming out of the lip. It had already been leaking there but this made it obvious. Originally I thought it was coming out of the thermostat housing, but I believe it was just dripping down from the lip to the housing.

First attached image- “channel” circled on left, “lip” circled on right. Thermostat housing and timing belt covers are removed.

Second attached image- zoomed out photo, circled the area that first photo is focused on.

Hopefully this all made some sort of sense, I can clarify anything if that’d help. I’m not sure what that channel is and can’t get in to see what the lip is or if there’s any way to seal it up. Not sure if I’m missing a plug or if there is a crack? Any input would be GREATLY appreciated.

Also I’m new here and not sure where to be posting, I also tried the sticky “3rd gen all questions allowed here thread,” hope that’s okay. Thank you in advance for any help!!!!

 

[Pyral]

Isn't that the water pump? If it is, that is a deliberate weep hole that they add so that when the water pump fails it wont drip onto the timing belt. Which means you need to replace your water pump asap.

I could be wrong, I don't have that engine, but it does look like it is coming off the water pump

 

[Jdog98]

I think you are right. The thermostat housing is connected to the water pump. I would replace water pump and thermostat housing

 

[Jdog98]

Thermostat housing/inlet may not be necessary if it looks ok

 

[Sonny.Deez]

Thanks guys, you’re right it’s the water pump. Posted something on reddit too, thought I had notifications going to my email for T4R.org but for some reason didn’t work.

Ended up ordering an ‘Aisin’ water pump/timing belt kit on amazon for around $200. Heard that’s a decent brand? Local NAPA had quoted 470 for a kit, not sure on brand

Now that I know that’s the weep hole for water pump, I’m pretty sure it’s been leaking from there the whole time… not the thermostat housing. It’s just tough to locate that leak when it’s barely seeping out… by the time it gets to the ground it’s all over a lot of crap!

 

[Endlessblockades]

Thanks guys, you’re right it’s the water pump. Posted something on reddit too, thought I had notifications going to my email for T4R.org but for some reason didn’t work.

Ended up ordering an ‘Aisin’ water pump/timing belt kit on amazon for around $200. Heard that’s a decent brand? Local NAPA had quoted 470 for a kit, not sure on brand

Now that I know that’s the weep hole for water pump, I’m pretty sure it’s been leaking from there the whole time… not the thermostat housing. It’s just tough to locate that leak when it’s barely seeping out… by the time it gets to the ground it’s all over a lot of crap!

Not to be That Guy, but it looks like your T-Stat jiggle valve is at 12 O'clock rather than 6 O'clock. My engine runs 10 degrees cooler at 6 O'clock (down). Since you're in there, you should try it. Most other Toyota engines recommend 12 O'clock, so it's common for mechanics to set them there. There are a lot of discussions about this quirk on this site, so don't take my word for it. Welcome to the forum.

 

[Pyral]

Thanks guys, you’re right it’s the water pump. Posted something on reddit too, thought I had notifications going to my email for T4R.org but for some reason didn’t work.

Ended up ordering an ‘Aisin’ water pump/timing belt kit on amazon for around $200. Heard that’s a decent brand? Local NAPA had quoted 470 for a kit, not sure on brand

Now that I know that’s the weep hole for water pump, I’m pretty sure it’s been leaking from there the whole time… not the thermostat housing. It’s just tough to locate that leak when it’s barely seeping out… by the time it gets to the ground it’s all over a lot of crap!

I’ve bought the Aisin water pump, you can literally see where they ground off the Toyota brand name. It’s the best option.

I would have ordered it off Rock Auto, no chance of counterfeits and they normally throw in a cool magnet too. The gasket should be metal.

 

[Sonny.Deez]

I would have ordered it off Rock Auto, no chance of counterfeits and they normally throw in a cool magnet too. The gasket should be metal.

Good to know thanks…. Will keep in mind for next time. I have a new account so I can’t make a new thread yet keep trying… but will post this here instead I guess…

I'm in the middle of replacing my timing belt / water pump on my 02 4Runner and just came across a possible issue. Was having trouble getting the nut off of the crankshaft pulley so I lodged the breaker bar up against the frame and bumped the starter to free it.
THEN after I freed the nut I bumped the starter once more to try to spin the pulleys to get the timing mark closer to where I needed it. Did I screw something up doing this? I went to manually spin the pulleys the rest of the way around with the breaker bar (see pic above) and got to a point where I really would have to force it to keep turning.
If it even would keep turning, almost didn't seem like it would. I know there's always pressure every so often while spinning but it wasn't just that.
I got the timing marks back to top dead center by spinning back counter clockwise but something is different ..that intermittent pressure you get while turning the pulleys is occurring right at top dead center... and don't think it was before? Could be wrong but don't think so.
Hope I didn't screw something up, if anybody has any suggestions or info l'd really appreciate, don't want to move forwards untill I figure this out.

Here’s a link to the Reddit thread I posted for a little more info—

https://www.reddit.com/r/4Runner/s/Pigd49lx8Z

 

[phattyduck]

I got the timing marks back to top dead center by spinning back counter clockwise

Never spin an engine in its reverse rotation direction. You can move an individual cam a bit in either direction (or completely around on the 5VZ since it is non-interference).

Remove the spark plugs - that will relieve all compression and you can feel what might be going on with the engine otherwise. At that point, you will only be fighting valve spring pressure, which is very minor compared to compression forces.

-Charlie

 

[Sonny.Deez]

Never spin an engine in its reverse rotation direction. You can move an individual cam a bit in either direction (or completely around on the 5VZ since it is non-interference).

Remove the spark plugs - that will relieve all compression and you can feel what might be going on with the engine otherwise. At that point, you will only be fighting valve spring pressure, which is very minor compared to compression forces.

-Charlie

Good to know , thanks… I didn’t rotate too far counter clockwise.. hope it didn’t cause more of an issue. I had previously turned at least 360 degrees and didn’t have any problems, felt the compression but nothing like this. Then I bumped the started couple times and when I went to turn it eventually just hit a brick wall.

Is it still worth trying removing the spark plugs? I guess I can’t hurt anything if I don’t force it once it hits that point.

Would this same thing happen if maybe the belt skipped or something and got out of time?

Thanks ,
Mike

 

[phattyduck]

Is it still worth trying removing the spark plugs? I guess I can’t hurt anything if I don’t force it once it hits that point.

Would this same thing happen if maybe the belt skipped or something and got out of time?

Thanks ,
Mike

An out-of-time 5VZ will not hurt anything. It is a non-interference engine - the valves can NEVER hit the pistons with the stock cams. The only damage from a broken timing belt could be to something in the timing cover getting bent/broken from the belt moving around. If the belt is still intact, that is not a risk.

Pulling the plugs is still a good idea. It will let you know how the engine is running and it makes turning over the engine much easier while doing the timing belt job. On the small chance that a liquid is in the cylinders (stuck open injector, etc.) it will keep you from hydrolocking and ruining the motor. Oh, and you can make sure the right plugs are in there (genuine twin tip NGK or Denso plugs).

-Charlie

 

[Sonny.Deez]

An out-of-time 5VZ will not hurt anything. It is a non-interference engine - the valves can NEVER hit the pistons with the stock cams. The only damage from a broken timing belt could be to something in the timing cover getting bent/broken from the belt moving around. If the belt is still intact, that is not a risk.

Pulling the plugs is still a good idea. It will let you know how the engine is running and it makes turning over the engine much easier while doing the timing belt job. On the small chance that a liquid is in the cylinders (stuck open injector, etc.) it will keep you from hydrolocking and ruining the motor. Oh, and you can make sure the right plugs are in there (genuine twin tip NGK or Denso plugs).

-Charlie

Awesome, pulling plugs now as we speak. So would you just continue as planned even though I can’t rotate the crank shaft a full 360 degrees? It seems like something has to be up.. but I triple checked all 4 of the spots I know of to check timing and they’re all spot on. Thanks for the help btw I really appreciate it.

Edit: Also, my account finally is old enough or whatever to post my own thread .. I’ll link to it here, I posted kind of an updated summary if it’d help at all. Thanks again

Problem While Replacing Water Pump / Timing Belt


Mike

Edit: got the plugs out, adding pics