Compression test

Looking to do a compression test on my 2012 Tacoma. Is there anyone who can give me a run down on how to. I’ve watched videos and have a general idea. Only thing is most videos were a little different. Has anyone done it to give me there experience and rundown or a video they recommend? Thanks

 

curious as to why do you want to do this?

 

What engine?
Pull the fuel pump relay for the 4.0
Or the C/OPN relay for the 2.7
Leave the relay out for the entire test.


Crank the engine over until it stalls.
Then do it once more.

After that test each cylinder.
For the 4.0 - psi should be around 189 psi.
145 psi minimum

I don’t know the specs for the 2.7
Maybe @Jimmyh knows?

 

Had some white/blue smoke come out the other day. Might be me but also feel like I may have some loss of power. Not much though and like I said could be me. Took to dealer and they said to just watch it for now, but I had the truck appraised and the notes said may have blown head gasket. So wanna see if all is good with this test without paying an arm and leg for dealer to test.

 

Thanks.... it is a 4.0

 

A compression test isn’t what you want for a blown head gasket.
You need to do a cylinder leak down test.
I’d start first with a coolant system test. It’s easier.

 

How is that performed and are the tools expensive?

 

The exhaust gas coolant test is relatively inexpensive The leak down test kit is a bit more, and takes quite a bit more work to do it. The directions and YouTube will help you out a lot here.

 

Thanks for the help

 

All good, I will add it is best to do with a warm engine. So if you did not just get done driving, start & idle until it reaches operating temperature. Then not wasting time pull all the plugs and start testing each cyl one by one. Also I hold the throttle to the floor as well. Crank until the gauge stops going up, usually 5-10seconds of cranking.

 

Im not saying you are wrong. There’s always more than one way to do it.

But the thought of pulling plugs on a hot aluminum head makes me nervous.
I’ve always done it cold.
And with a leak down, it’s going to be cool(er) by the time you get all the cylinders to TDC?

Maybe I’ve been doing it wrong???

 

2.7 liter 2TR-FE Engine.

Compression Pressure: 178 psig.

Minimum Pressure: 128 psig.

Difference Between Cylinders: 10 psig.

 

I have always done on a warm engine. By the time I get my tools out and the coil packs off its more like warm.

You can totally do it cold, but the numbers will read slightly lower as things expand to their proper clearances when warm. The spec limit numbers in the service manual are “warm” at least on the Hondas, Toyotas, & Subarus I have worked on.

I have not had issue with plug/head threads, but I have heard other people mention this as a concern. Guessing modern Toyota metal quality is good enough its not a concern.

 

After seeing a Ford 4.6 blow 2 plugs out. I definitely take precaution now.
I believe the 5.4 had this issue as well. My understanding is there weren’t enough threads when using Aluminum heads. I believe the 3 valve engine were better.

But until I seen that happen, I never really worried.
Now, I get nervous. Because that’s not a repair job I want to do.

 

OP, from day one with only a couple of miles on my new '14 V6 I would occasionally see some blue/white smoke in my rear view mirror(s) on start-up. Others have reported this as well on both new engines as well into getting some miles.

It turns out that I narrowed it down to this occurring when the truck was parked on a small incline with the front a bit higher.

When I latter had the RH valve cover off it appeared that oil could pool a little near the rear valves as it drained back from a slightly elevated front and possibly seep down through a valve stem seal and down a guide. It only takes a very tiny bit of oil to get some blue smoke. That was my best guess.

 

I’ve seen many times the plugs ripping the threads out of an aluminum head. To avoid damage and a potential need to helicoil repair, what you could do is remove the plugs cold, put them back in with anti seize. Then after you warm up the engine, hopefully the plugs will come out without issue.

 

Every video I have watched said to do this while engine is warm but now you guys have me worried. Definitely don’t wanna strip any threads. Should I do this cold or would I be ok if the engine is just a little warm? I want it to be accurate.

 

I'm in agreement with this opinion. Test coolant for exhaust gasses first.

If you've already replaced the plugs, you didn't have damaged threads then, put new ones in with anti seize, your probably ok to pull them out hot. Use common sense. If it feels like you're ripping the threads, stop.

 

So what does the coolant test provide? What will it show me if the levels are off?

 

It will show you that you have exhaust gases entering your cooling system. This is typically how the gasket fails.


Is your coolant level ever low?
I don’t put a lot of faith in an “Appraisal”.
Smoke out the exhaust pipe doesn’t mean much. There are a multitude of things that can cause that. Most are much less severe than a blown head gasket.