Overheating ! - Page 3 - Toyota 4Runner Forum

Cree · 11-14-2021, 03:06 PM

Quote:

Originally Posted by tpelletier

Compression test results:

1: 199
2: 116
3: 179
4: 189
5: 199
6: 186

And pic of Cyl 2 spark plug

Now how do i know if i need to replace heads or just the gaskets ?

The color near the base of the strap shows burning coolant. My money would be on a head gasket. No really good way to tell without tear down. You'll see the failure point on the gasket. If you don't, you'll want to get the head fluxed. If your oil is free of water, it's going to be either the head or the gasket MOST LIKELY. Typically if a cylinder cracks you'll get water in the oil.

spartacus · 11-14-2021, 03:47 PM

It could be the gasket but usually two adjacent cylinders show weak compression numbers.I could be wrong.
Pour a tea spoon of oil in #2 if you get higher compression then the rings could be the culprit. If the compression numbers don't increase much then it could be burnt exhaust valve, or intake valve due to overheating.
Unfortunately removing the heads and examining would be the only way, IMO.

tpelletier · 11-14-2021, 07:04 PM

Quote:

Originally Posted by Cree

The color near the base of the strap shows burning coolant. My money would be on a head gasket. No really good way to tell without tear down. You'll see the failure point on the gasket. If you don't, you'll want to get the head fluxed. If your oil is free of water, it's going to be either the head or the gasket MOST LIKELY. Typically if a cylinder cracks you'll get water in the oil.

Quote:

Originally Posted by spartacus

It could be the gasket but usually two adjacent cylinders show weak compression numbers.I could be wrong.
Pour a tea spoon of oil in #2 if you get higher compression then the rings could be the culprit. If the compression numbers don't increase much then it could be burnt exhaust valve, or intake valve due to overheating.
Unfortunately removing the heads and examining would be the only way, IMO.

Alrighty, Ill check the oil for water and do that oil test.
In the meantime I am ordering a full gasket kit on Rockauto.

Question: If I am opening up the heads, should I might as well replace the problematic head as well ?

Thanks again y'all

spartacus · 11-15-2021, 09:51 AM

Quote:

Originally Posted by tpelletier

Alrighty, Ill check the oil for water and do that oil test.
In the meantime I am ordering a full gasket kit on Rockauto.

Question: If I am opening up the heads, should I might as well replace the problematic head as well ?

Thanks again y'all

If the head is flat no cracks it should be good. But getting it skimmed is an option that might be cheaper then buying a new head. I dont know cost wise what would be better. Call machine shops near you that do head resurfacing.

Bad Luck · 11-15-2021, 09:55 AM

Quote:

Originally Posted by tpelletier

Compression test results:

1: 199
2: 116
3: 179
4: 189
5: 199
6: 186

And pic of Cyl 2 spark plug

Now how do i know if i need to replace heads or just the gaskets ?

Do a cylinder leak down test on cylinder number 2 with a cold engine and the radiator cap off. It's possible to have a failed head gasket where it fails between the cylinder and a coolant or oil passageway and only affect one cylinder.

19963.4lsr5 · 11-15-2021, 11:11 AM

Quote:

Originally Posted by Bad Luck

Do a cylinder leak down test on cylinder number 2 with a cold engine and the radiator cap off. It's possible to have a failed head gasket where it fails between the cylinder and a coolant or oil passageway and only affect one cylinder.

The 97 SR5 project was that way. One cylinder with antifreeze pooled in a cylinder.

On a side note….since I bought the 97 knowing it’s engine was toast, I just pulled it and put it on a stand and pushed it into a corner. Big mistake. The antifreeze in the oil pan caused both intake cams to rust before I broke it down to rebuild. It sat almost two years. I won’t do that again.

Sent from my iPhone using Tapatalk

Site Navigation