compression test and a leak down test cost?

J

judoant

Member
235k on the truck. For the past 2 years I would get a rough idle at start up for about 30 seconds and it would go away. No check engine. Over the past 6 months the same occurrence has become more frequent. It happened last night and threw a check engine. Pulled the P0306 code today. I see many threads about head gaskets being the cause.

How much should I expect to pay for each a compression test and a leak down test?

I replaced the plugs and wires 2k ago.
 
Register to hide this ad
judoant said:
235k on the truck. For the past 2 years I would get a rough idle at start up for about 30 seconds and it would go away. No check engine. Over the past 6 months the same occurrence has become more frequent. It happened last night and threw a check engine. Pulled the P0306 code today. I see many threads about head gaskets being the cause.

How much should I expect to pay for each a compression test and a leak down test?

I replaced the plugs and wires 2k ago.
Click to expand...

you could easily do this on your own. Go to autozone and rent the tool. Its really easy. Ever replaced spark plugs? also there is a chemical test. To test if exhaust is leaking into coolant. Combustion leak. I picked one up from advanced.

https://www.amazon.com/Lisle-75500-Combustion-Leak-Detector/dp/B0007ZDRUI
 
From what I can tell the leak down test will tell me everything I need to know as far as something leaking within the engine.

The leak down test states connecting the kit to any vacuum line. I have never done this so I am not sure where this would connect.
 
I would take [MENTION=99565]kolelt[/MENTION] suggestion and rent a compression tester for free. I don't know if they also rent leak down testers but you might not even need one if your compression test results are good. A leak down tester also requires you to have an air compressor just to let you know.

I can't help you with a video for doing leak down testing but [MENTION=102606]infamousRNR[/MENTION] and I do have a video for performing a compression test. This is an easy thing to do. Just like [MENTION=99565]kolelt[/MENTION] said above, if you can replace spark plugs, you can do a compression test.

Here's the video:

<iframe width="560" height="315" src="https://www.youtube.com/embed/ky7bndfFpO0" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>
 
My former local Autozone used to rent leak down testers but the one in my new town doesn't. If you suspect a HG leak, perform a coolant pressure test. Losing any coolant?

The compression test is a good baseline to start with. Maybe Tim and Sean can add a leak down test video to their arsenal for 2018.

A pretty thorough explanation of both tests:
LC ENGINEERING Carburetor Tech
 
I am not sure about the coolant. I plan to start keeping an eye on it. The radiator is full and the reservoir is empty.

I am going to try the amazon leak down tester suggested and look to do a compression test. Once complete I will post the results.

Either way this rig has 235k and if requires a $2500 HG repair I am not sure I can justify that cost. It is in such good shape though., with the lift, bumpers, and newer front leather seats, it really breaks my heart. A 5th gen or Sequoia may be in my near future.
 
just did a compression test. Her are the results. I was expecting a larger variation given my symptoms. I have swapped the 5 & 3 coil packs and have the battery disconnected to reset the CEL. My thought was to see if the CEL code follows the coil pack.


5= 200 6= 205
3= 190 4= 185
1= 200 2= 185
 
The coil pack is a start.

Fill up the reservoir with coolant. Check the condition of the radiator cap as well, it may need a new OEM one.

With the good numbers, it may be a leaking injector, where it is dumping too much fuel into the chamber at startup but the excess is burned off when the engine begins to warm up.
 
judoant said:
just did a compression test. Her are the results. I was expecting a larger variation given my symptoms. I have swapped the 5 & 3 coil packs and have the battery disconnected to reset the CEL. My thought was to see if the CEL code follows the coil pack.


5= 200 6= 205
3= 190 4= 185
1= 200 2= 185
Click to expand...


Do the chemical test also.
 
judoant said:
I filled and marked the coolant reservoir.

I performed the leak test with

https://www.amazon.com/Lisle-75500-Combustion-Leak-Detector/dp/B0007ZDRUI

but I am not sure I am doing it right.

When I create so much of a vacuum it actually compresses the top radiator hose to the engine i sucks some coolant in and instantly turns yellow. When i use a manual suction and hold the tube tight to the radiator to create bubbles it never turns yellow.???
Click to expand...

pretty sure with the chemical, you need to fill some of the chemical inside the rube, then the other rubber part you hold tight over the radiator. If combustion is leaking into your coolant, the blue will change colors. This is not a leak down test by the way. Its a combustion test.

https://www.uview.com/site/ywd_uview/assets/pdf/99081870_comb-leak.pdf
 
if squeezing the top radiator hose causes the fluid to change colors do I have an issue? Its practically pushing coolant into the test kit tube when I do that.

If I hold the test kit tight to the radiator and use manual suction to create bubbles it never changes color indicating an issue.
 
judoant said:
if squeezing the top radiator hose causes the fluid to change colors do I have an issue? Its practically pushing coolant into the test kit tube when I do that.

If I hold the test kit tight to the radiator and use manual suction to create bubbles it never changes color indicating an issue.
Click to expand...

You just need to fill some chemical to cylinder. Then the other end goes over the radiator or reservoir. If exhaust fumes are getting into the coolant. Than it will change color indicating a issue !
 
You're describing classic symptoms of a bad head gasket or crack head. Sounds like you have coolant leaking in while it sits. The rough idle you're feeling is that coolant burning off. Once the coolant is burned off the engine will smooth out. I've been there in the past on another vehicle, and I'm about to dive into this same project on my 4runner.

If you're concerned that you may have coolant leaking you don't need any kind of test to get the results, but you will need someone to help you out. Pull your plugs, and crank the engine. Look to see if any coolant shoots out when you crank it. If so you found your leak.
 
Last edited:
The rig has been sitting for the past week and not driven. I started it today for the first time in 5 days. If I was leaking coolant wouldn't it have stumbled on start after sitting for so long?

I will be back to driving it regularly now so we will see what we get. Hopefully if it throws another CEL it will follow the coil pack I moved to another cylinder.
 
MStudt said:
You're describing classic symptoms of a bad head gasket or crack head. Sounds like you have coolant leaking in while it sits. The rough idle you're feeling is that coolant burning off. Once the coolant is burned off the engine will smooth out. I've been there in the past on another vehicle, and I'm about to dive into this same project on my 4runner.

If you're concerned that you may have coolant leaking you don't need any kind of test to get the results, but you will need someone to help you out. Pull your plugs, and crank the engine. Look to see if any coolant shoots out when you crank it. If so you found your leak.
Click to expand...



I basically did this when I did the compression test. All plugs were removed before I tested each cylinder. I never saw any fluid shoot out.
 
After a couple of weeks with no rough idle at start it came back the last few days. It progressively became more rough and today it finally threw a CEL.

Unfortunately it is still on cylinder 6 even though I swapped coil packs.

I also filled and marked the coolant reservoir a few weeks ago and it appears it is about 1/2" lower now.
 
Last edited:
Any follow up to this?
If it didn't follow the coil pack, sounds like it's specific to that cylinder. 205 is a good number, so did you try a new injector?
The reservoir may be a bit lower simply due to the coolant in the engine being too low originally, and now it's evened out. Check from that level now.
 
I had both 4runners beside each other a few weeks ago in the morning and fired them up. One has previously overheated with a suspected blown head gasket. That one produced noticeably more white smoke than the other one which I know is good. Is this definitive proof? The suspected blown head gasket runner has old gas in it that sat all winter. Could the white exhaust be from moisture in the fuel? Other than this possibility, I think this is 100% proof that it has a head gasket problem. Now it's just a matter of digging in to find the problem. All because of those stupid coolant lines to the rear heaters that rusted out and lost all the coolant.
 
You must log in or register to reply here.

Members online

Total: 388 (members: 6, guests: 382)

Forum statistics

Threads
278,307
Messages
3,554,053
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top