I am going to dive into some maintenance this weekend on my 250.

I will be replacing my spark plugs as I am at 116k now, but since I will be taking off the intake manifold I figured I would do a top clean on the valves at the same time. I am not experiencing significant knocking, but it is slightly present and since I will have it apart...why not.

I have done plenty of searching around the forums, but rather address things directly.

Planned maintenance:

• Chemical clean of intake valves (manual)
  • Siphon out the chemical and junk
• New spark plugs
• New Upper / Lower intake manifold gaskets
• Clean throttle body
• Clean mass air flow sensor (MAF)

Parts to be used:

• Denso FK20HBR11 spark plugs
• Fel-Pro MS97084 Intake Manifold Gaskets
• New crush washers for fuel line on intake manifold
  • Toyota OEM 9043008014
• Berryman 3012 B12

Post-maintenance:

• Oil change
• Berryman B12 in fuel tank
• Fun

Questions:

• What size socket do I need to turn the engine to open and close the valves?
• Can someone direct me to a diagram of the engine's pulley's?
• Any advice on doing the manual chemical clean of the intake valves?
• Other misc. advice?

In the coming week's I'll be tackling the water pump...

Thanks in advance!!!

 

Here is an update...

The day ran long as I ran into two issues taking off the intake manifold.

First was a stripped Allen bolt (the back one). Thanks to the quick responses here I was able to drill it out and had the head of the bolt come off.




I also had an Allen key break off in another bolt. Nonetheless, I was able to get that out too.

It seems the bolts were over tightened by whomever serviced the vehicle previously.

I took the plugs out. I am not sure if they were replaced but I am assuming they were as they don't look too bad.



Tomorrow I will tackle the valve clean. All of them are about the same as this one...one is really gunked over.

 

Looking forward to updates. I always like to see options for valve cleaning instead of walnut blasting. just bought a 08 250 with 101k on it. No siges of issues but plan to have the car for a while so I may be doing this at SOME point.

 

I'm working on getting the car running...I have another thread going regarding the car not firing up.

https://www.clublexus.com/forums/is-...-no-codes.html

Here is the best shot I was able to get regarding the valve clean up...This is the same one as before. Note, how clean that stem looks. =D

 

+1 I also would like to know how you cleaned the valves. They look brand new.

 

OP that came out A LOT better than before. How did you clean them exactly? Mixture of manual scraping and letting some sort of cleaner soak in?

 

I used Berryman B12 on a soak for 30 mins followed by a light scraping session every 15 mins. I did this on three different intervals. I used less than 1 oz per valve.

I am really happy with how they turned out...how does the car run? I am not sure as the car still isn't firing up.

All-in-all, there was a huge amount of carbon removed from the valves, I wouldn't say it is a 100% perfect, but the process and procedure isn't that bad at all, just some patience and time.

I will say...I'm getting pretty good at disassembling and reassembling down past the lower manifold now.

 

To close this one out...

I had some issues getting the car started after working on it over the weekend, but I was able to get it to fire up last night. I followed up with what I had to do here: https://www.clublexus.com/forums/is-...-no-codes.html

I still need to install the new spark plugs, but I was more concerned with getting the car running again.

Nonetheless, the valve clean and project was well worth my time. I can notice a huge difference in both idle and acceleration.

The idle is smooth as butter and the acceleration is more responsive than before.

I am going to get an oil change at the end of the week, but run some Seafoam through the oil in the meantime.

I am not sure how the previous owner fully maintained the car, but happy to get hands on and maintain it to my standards.

 

How was your idle before doing this? My wife's 250 with 101k mi on it seems to idle fine and no egg smell or smoke during WOT pulls. So Im hesitant doing all this if I dont have to lol our car idles like a smooth sewing machine lol

 

I would notice a slight shimmy while at idle and would get the egg smell under WOT. My line of thought was..."I'm having to disassemble the manifold to get to the spark plugs," plus accessing the valves is like 6-8 nuts and bolts away.

When I saw the amount of carbon on the valves...I was like "Oh yeah, I'm doing this." * Note the before and after photos.

The idle is so smooth now.

Let me know if you have any other questions.

 

Where did you get the B12? Is it save to dump in the gas tank?

 

Here's a link to the B12:

Yes, you can dump this into the gas tank. That was my initial plan, but I ended up using it all on the valve soak.

I should caution if you use a wire brush, make sure the bristles DO NOT come off from the scrubbing.

I'm not sure what kind of damage those little metal hairs can do, but I can attest that it is not fun probing with a magnet to pick all of them up.

 

did you use a fuel pump to get out all the carbon? what type of brushes you used to get in there?

I've seen videos on the water pump, looks like a PIA

 

Here is a link to the siphon I used to get the carbon out:

I significantly cut the hose down that it came with.

The carbon did not come out in chunks, it was completely liquefied by the B12. The solution was black as pitch.

I believed it helped to do intermittent scrapings with the wire brush plus that agitated the solution.

It is somewhat of a tight space down by the valves.

The wire brushes I used were 7mm in diameter stainless steel. I had a hard time finding these local and I stayed away from copper ones.

 

As a final, final thing to note...

When I was having issues starting the car last week, as part of the troubleshooting I reverted back to the old spark plugs. I replaced them over the weekend and man, car seems even smoother, throttle response is better and possibly MPG has improved.

I also added ~7 oz of Seafoam to the oil and will be getting it changed this week after ~300 miles.

Good stuff Maynard...