Compression test...

[LittleCaesar]

I am going to be performing one on a friend's gf's 2000 V6 either this weekend or next week. It looks to be as easy as removing the coil pack wires and plugs, then keeping the TB wide open and then cranking away five times beginning with CYL #1. Never done one on this engine.

Am I missing anything or is there a better way?

I am thinking her engine needs a valve job (151,000 miles) but it idles fine and only burns a small amount of oil at highway speeds. She did hear some initial valve chatter a couple of times last winter during the first crank of the day.

 

[IanB]

Pull the fuse for the fuel pump, do the test with a warm engine, and crank until the gauge stops rising (that may or may not be 5 cranks), but do it the same for each cylinder.

 

[YotaZach85]

Ian nailed it.

You may want to do a leak down test though you'll be able to tell for sure if compression is leaking out and you'll be able to tell where it's going, too.

 

[LittleCaesar]

Thanks for the tips. I'll report back with some numbers here within the week.
Hopefully the compression test will tell me if it is a valve or if oil is getting by the rings.

I have never performed a leakdown test but have seen the testers before.
Any good specific brand tester out there or will the go to el cheapo HF special work OK?

Having personally changed out the valve cover gaskets on this 4 runner, I can say the valves and cams are quite clean. My friend says it consumes about 1/3 of 1 qt every 6 months. It may just be a result of the engine getting up there in age and miles.

 

[J-money$$$]

Thanks for the tips. I'll report back with some numbers here within the week.
Hopefully the compression test will tell me if it is a valve or if oil is getting by the rings.

I have never performed a leakdown test but have seen the testers before.
Any good specific brand tester out there or will the go to el cheapo HF special work OK?

Having personally changed out the valve cover gaskets on this 4 runner, I can say the valves and cams are quite clean. My friend says it consumes about 1/3 of 1 qt every 6 months. It may just be a result of the engine getting up there in age and miles.

Sound like its rarely driven, or rarely maintained. I hope the first. Mine consumes about a quart every 2,000 miles. Its been doing that for awhile. I would only do the compression test if you had a serious problem. A small amount of oil loss is not too much

 

[LittleCaesar]

J-Money,

I agree. It sees at most 7,000 miles a year. Oil changed every 6 months. My friend and his GF commute together in his Civic EX to save gas since they work less than three miles apart.

I think my friend and I are planning to give the 4runner an Italian tune up tomorrow and see how much oil is in the pcv catch can afterward. If little to none at all, he may switch from Castrol GTX to GTX high mileage to see if that will help any.

 

[J-money$$$]

J-Money,

I agree. It sees at most 7,000 miles a year. Oil changed every 6 months. My friend and his GF commute together in his Civic EX to save gas since they work less than three miles apart.

I think my friend and I are planning to give the 4runner an Italian tune up tomorrow and see how much oil is in the pcv catch can afterward. If little to none at all, he may switch from Castrol GTX to GTX high mileage to see if that will help any.

The high mileage oil helps in mine. I buy it when its on sale. =) I put synthetic in it once, and it consumed/ started leaking almost a quart in 100 miles.... Old motors dont like synthetic....

Well hopefully your compression test numbers look good

 

[brian2sun]

My friend says it consumes about 1/3 of 1 qt every 6 months. It may just be a result of the engine getting up there in age and miles.

That's nothing to worry about. Normal for a 150K motor. Hell, 1/3 qt. in 6 months is pretty normal for a 50K car.

 

[IanB]

Thanks for the tips. I'll report back with some numbers here within the week.
Hopefully the compression test will tell me if it is a valve or if oil is getting by the rings.

Forgot to mention, if you do have a cylinder low, throw a cap of oil down that hole and repeat the test, if the numbers come up in-line with the rest you know the problem is the rings, if there is little change, it's a valve seal or head gasket issue.

 

[YotaZach85]

I have never performed a leakdown test but have seen the testers before.
Any good specific brand tester out there or will the go to el cheapo HF special work OK?

Should work ok. I would do the compression test first and if you find a low cylinder do the leak down, you can usually listen and find out where the air escapes from.

Sound like its rarely driven, or rarely maintained. I hope the first. Mine consumes about a quart every 2,000 miles. Its been doing that for awhile. I would only do the compression test if you had a serious problem. A small amount of oil loss is not too much

Mine with 230k only used half a quart every 4k, I normally didn't have to add any oil between 4k changes.

Forgot to mention, if you do have a cylinder low, throw a cap of oil down that hole and repeat the test, if the numbers come up in-line with the rest you know the problem is the rings, if there is little change, it's a valve seal or head gasket issue.

I forgot that as well, it's been a while since I've done a compression test.