Ok i finally had a chance to take out the plugs on my Runner today and do a compression check. Im losing coolant like crazy so i feared the worst.......#1 cylinder 150, #2 135, #3 150, #4 135, #5 could not get my gauge on it, #6 160 and spewing out antifreeze. Why such high compression on # 6? I mean i know now that its difinately head gasket or head but just wondered why the high pressure . So i guess its time for a 3.4 swap if i can round up enough money to do it. Just thought i would throw that out there and see what you guys think.

 

Is yours covered under the head gasket recall? What year is it?

The compression is higher in #6 because the compression area is smaller due to the antifreeze and it also is a better seal to the rings.

 

You can call Toyota customer service to see if your head gasket was ever serviced before(if you're not the original owner).I checked my 91 4R 3.slow and was told it was done 60K miles ago in 1999.Good luck.

 

Definately check for the recall.

I agree with Yoda, the antifreeze is making the rings seal better boosting compression.