PennSilverTaco's "Perfect 5-Lug Regular Cab" Build, Aspergers, and General BS MegaThread!

I went from a 95.5 4x4 5spd 2.7L to a 2010 4x4 AT 4.0L and saw a noticeable drop in fuel mileage. Really really enjoyed my first gen but it didn't have factory AC so I sold it. Otherwise i'd be running it to this day.

 

Ok.....allow me to lead you a bit more......

You have stated:
oil consumption is sporadic and occurs more in hot weather.
"oil" is in the coolant reservoir
No visible leaks
134 kmiles
Mechanic verified its not the tranny cooler leaking in the radiator.

Have you done a Leak Down test on the cylinders? Nothing has been stated as such.
Have you done a pressure test on the coolant system? Nothing has been stated as such.
How did the mechanic verify the tranny cooler wasn't leaking in the radiator?

Things you should know:
In winter temperatures, gaps will shrink as materials contract.
Fluids/Gases will only move from high pressure into low pressure.
There are several areas in an engine where oil and coolant are close to each other.

Logic Applied:
It is summer with higher temperatures meaning gaps are larger. Only a couple places where pressure in an engine is greater than the coolant system and coolant/oil/fuel is in close proximity. Temperature and pressure will open gaps. The COMBUSTION CHAMBER. The only component to separate the two is the head gasket. A head gasket will not show visible leaks.

All the symptoms fit. Run a Leak down test on the cylinders, open the radiator cap, watch for bubbles. Might be able to see with engine running. Do a cooling system pressure test. Without visible leaks and a falling pressure...........

Vaporized fuel could be pushed thru the head gasket into the coolant during the COMPRESSION stroke. The fuel in the coolant may not burn due to the volatiles have been boiled off.

At 134 kmiles the piston rings could be allowing oil into the combustion chamber as a vapor.

 

My mechanic is going to be running all of those tests when it goes in for an oil change and coolant flush next week; I will be driving the truck very sparingly until that time.

 

Yes flushing the coolant and changing the oil is a good idea, and yes monitoring is good too. But taking a sample and sending to a lab for analysis is a good way to determine what actually is in the coolant, rather than sitting around and waiting to figure out what it is.

If you have the appointment for next week, consider asking your mechanic to take a sample of each fluid. Blackstone labs will send you the kits for free, then you pay $30 or so when you mail them in and they deliver the analysis. If the test kit doesn't arrive in time, then can always collect in a clean container and hold while waiting for the test kit

 

I sent way for a Blackstone oil testing kit back in like 2019 and ended up not using it; Still have it and will use it. Also will send away for coolant testing kit...

 

Cool, if you already have one thats great. If the second kit doesn't arrive in time, then a clean container will store the coolant sample safely until it arrives

 

How do I get the coolant sample?

 

You'll learn to love the 1st gen even more.

 

It's also a moot point right now because she totaled her car and the Tacoma is her only means of transportation; I refuse to pay the inflated price most sellers are asking!

 

Yeah, high prices for 1st gens on top of covid prices. It's a bit ridiculous.

 

Yes to all the questions except the timing belt, but the best MPG I've ever gotten in my truck in the last year is 22 on the highway...

 

My uncle put A/C in a 1991 Toyota pickup that did not previously have it; Don't know if it's any easier or harder to install it in a Tacoma...

 

Theres a drain at the bottom of your radiator.

In an ideal environment, you would open it when cold to prevent potential for burn from coolant. but because you potentially have some contaminates that aren't consistently mixed/float to the top, you may want to take the sample hot after driving for 20 or so miles. You can open the drain with the coolant hot, I've done it before when flushing the coolant without removing the thermostat. Just be careful that there is a deep drain pan underneath to prevent splashing and that you wear some gloves in case it does splash up on you

This is mine flushing the green out when some mechanic put in the wrong coolant. This was a hot drain, so as you can see it does splash a little

 

Also, any idea how oil sludge would have gotten into the coolant reservoir?

 

See the last line of post #40.

 

Okay; That explains how the truck is burning oil virtually unnoticed, but it says nothing about there would be oil sludge in the coolant reservoir...?

 

Oil vapor could be pushed thru the head gasket along with fuel vapor during the compression stroke. Oil is designed to combine with impurities from combustion, it may combine with minerals in the coolant system to form sludge..............in the coolant system........

Oil is a fluid, it can exist in liquid form or in vapor form. Gasoline has similar fluid properties.

Although this is firm logic leading to a potential root cause, it all remains speculative until tests are complete at the mechanic and results from Blackstone.

 

At the time that I owned the truck it would have been cheaper to sell and buy another with A/C. Now with the price of first gens... Probably not.

 

The internals of a cylinder/combustion chamber is very chaotic.

Consider.....at 2000 rpm a 4 stroke engine requires 2 revolutions to complete the cycle. In 1 revolution the piston will make 1 up/down cycle or 2 strokes of the 4 cycle. The time to complete 1 stroke is 60/1000 of a sec. During this time, the piston will compress the air/fuel mixture to the engine's compression ratio. For simplicity lets assume 10:1. This means the compression pressure is near 150 psi. Then the spark ignites the fuel mix to drive the pressures into the 4 digit range. This is just 1 cylinder, now imagine, you have 4 cylinders that must work together in perfect time.

150 psi at 200*F will drive oil/fuel vapors thru a gap in the head or cylinder wall or head gasket. This gap may not show in a cold engine that is not running.

An engine is a dynamic, volatile beast that has been tamed and controlled to our benefit.