4.0L V6 1GR FE burning oil

2 major obvious signs of a water pump failing are:

- Crystallized dried coolant trails below/around the water pump shaft seal. (Visible w/ good lighting.)

- Bearings going bad, which may sound like gravel or rocks rolling around in the pump:
https://www.youtube.com/watch?v=v-f4bQBzI7o

 

Sorry for the delay in replying @2ndgenron, had a bout of Covid run thru the house and I was off my usual morning routine which includes reading TW.

Anything up front of the engine with bearings can leave you stranded someplace, but I haven’t seen a post from anyone indicating that a water pump had done them dirty in that regard. Their failure mode seems to be non-catastrophic leaks. The idler pulley and tensioner bearings are more likely to go than the water pump bearings, again if posts on TW are to be used as statistics.

Then again, on my Taco, I had my alternator seize up sitting in my driveway shortly after I had taken a trip to Death Valley (just after replacing all of the idlers and the tensioner bearing). So anything can happen even on what was at the time a 114K 10-yr old “trusty” Tacoma. But I think mine was a less common situation, but your engine has 2x the miles. If it’s never been replaced, I’d probably put that on the list of things to do when you have some downtime and working on the truck is a reasonable use of that time.

 

Thank you for the response! I’m currently at 266k miles. It rained heavily here in Southern California and one of my U joints went out. Replaced all 3. I will be extra vigilant on the tensioner and idler pulleys. There’s a sound the water pump makes that can be use as a diagnosis of the pump going bad. Also, every time I start the truck and put it into drive there’s a subtle sound coming from the transmission ? Or center console, I do not know how to explain the sound. Everything else is ok for an over a quarter of million mile truck. This is how she stands as of yesterday (don’t mid gas prices)
Cheers

 

Appears to be a lot of paranoia in this thread. There has been no issue revealed. Why experiment with an engine flush and the risks that are involved? Why bother with a compression test if no indication has been given, was stated it pulls hard, no indication of leaks? How did the spark plugs look when swapped?
Sending a sample to Blackstone is a worth while endeavor for piece of mind and may steer towards a specific oil.
From the looks of the exterior there is good indication that the prior owner cared, but is not proof.
Toyota has some crazy standard of 1qt/1k mi as acceptable on certain engines. That is a bit much IMO. Could become an issue if on an extended road trip and reading oil levels every couple fill ups is not performed.
Looks like you bought a nice high mileage truck that should be good to go.

I push ~9lbs of boost w/ 211k mi. My small catch can is half way full after a couple thousand miles. But mostly moisture from the short commute I now have. I add ~1qt between changes; every 3-5k mi. Valve guide seals may be a bit leaky and I have a couple very light oil leaks.
Compression test was near perfect across the board.

 

Good way to approach things. Seems like a well taken truck. High miles was making me a bit paranoid since it’s my first Tacoma. Owned other Toyota models with high miles that had thirst for oil. Spark plugs were impecable when swapped.

 

Run Mobil high mileage 5w30 or valvoline syn and see what happens otherwise I would leave as is

 

Here's an update w/ less speculation & more data. I pulled an oil sample during last oil change (at ~3600 miles) and sent it to Blackstone Labs for analysis, including the supplemental TBN report (another $10.) Redacted all my PII using a PDF editor, that's why the name, client ID, etc. are blank.

2014 Tacoma 4.0L V6, ~78K miles, 5W-30 Kirkland™ (COSTCO) synthetic oil

TL;DR: an excellent oil-analysis report.

Based on this, it looks like a 3-3.5K mile OCI is overkill and a waste of money for my particular Tacoma. I'm going to run a 5K-mile OCI & continue to send in samples to Blackstone every 20K miles or so.

Notes:

- Blackstone takes quite a while to process samples. About 3 weeks from the time my (tracked) sample arrived at their receiving address.

- Report shows very low amts. of fuel-in-oil, yet I can still smell gasoline in the oil when I pull the dipstick. I guess this is just a nose-sensitivity measure since gasoline has an extreme pungency to it. The "<0.5%" measure on the report calculates out to <5 teaspoons of gasoline in 5.5 quarts (1056 teaspoons) of oil. I'm sure if I dumped a few teaspoons of gasoline in 5.5 quarts of oil & thorougly blended it, I'd be able to smell the gasoline easily.

 

I would say 3500k OCI is a bit of an overkill. I just replaced the oil about 500 miles ago or 2 weeks, with Mobile 1 extended protection full synthetic for high mileage vehicles. Have not seen any changes in dipstick so far since oil change. Also, about a month ago I found out the oil pan was damp, might be a seepage so possibly this is affecting oil levels passed 3000 miles? I’m guessing the rear main seal needs to be replaced. See pictures below. This would make me happy knowing the root cause is rear main seal and engine is not actually consuming oil. See photos below