Head gasket question 2007 4runner V6

Drcoffee

Drcoffee

Senior Member
Im a little confused with my 07 4runner V6. I have just bought a truck with 222,000 miles. I found a leaking radiator and water pump. I have replaced them. When I start the engine, there seems to be more steam than normal, they it fades, then normal amount of vapor coming out until warmed up. I also see some white ash in the tail pipe. And #6 spark plug looks like it has a little residue that the others dont. So I assume my #6 head gasket has a small leak. There is no rough idle or CELs as others report. It runs strong. The coolant resevior never gets pressurized and never too much coolant in it, right at the hot level. But I cant tell if Im losing coolant because its getting colder lately, but its never empty, not yet.

Is it possible to burn coolant in #6 but not get pressure in the cooling system? If its leaking into the cylinder on cool down, it must be pressurizing the cooling system when running. Am I right?

I dont know if this has any importance, but my long term fuel trim is 0% B1 and 7.8% B2. Down stream O2 sensors seem to be slow so I will replace them soon. I wonder if a coolant leak on B2 has damaged the up stream O2 sensor.

Im tempted to add some Bars head gasket sealer, but not if its not a head gasket issue.

Any help from those with prior experience would be appreciated.

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Your post doesn't say, so it's not clear to me that you're losing coolant, I wouldn't do anything until you see clear symptoms of head gasket failure, your 2007 V6 T4R was built after Toyota redesigned the head gaskets which was 12/05 and I haven't seen any 2007 V6s reporting head gasket failure.
 
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AuSeeker said:
Your post doesn't say, so it's not clear to me that you're losing coolant, I wouldn't do anything until you see clear symptoms of of head gasket failure, your 2007 V6 T4R was built after Toyota redesigned the head gaskets which was 12/05 and I haven't seen any 2007 V6s reporting head gasket failure.
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agreed, dont add sealer or worry too much until there are definite tell tale signs of a bad h/g. 2007 should not have the issues earlier models had.
 
Im not blowing coolant out the resevior so I will continue to drive it and monitor it. Its not my primary vehicle but I will come back with updates. Thanks for your input.
 
I have noticed white residue in my tail pipe. Thats a good idea to test the coolant before throwing any more money at it.

I can hear a high pitch whistle coming from the drivers side intake. I think I may have a vacuum leak either at a fuel injector or plenum gasket. Once I find out about the head gasket, I will tackle the vacuum leak.

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Try getting an oil analysis done smith blackstone labs. They’ll be able to tell you if there’s coolant in the oil
 
Drcoffee said:
Thats not a bad idea. I have checked the oil and it looks clear and no froth/foam so far.
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On one of my oil analyses I did they found a high concentration of potassium which lead them to believe it was coolant in the oil and I may have a HG leak. It was right after I had my water pump changed. I don’t know why or how coolant got into the oil, but I have a 08 so HG isn’t common. I changed the oil again and got it checked and there was still a trace amount but much left. They said if I did the repair, it may just be a little residual. One more oil change after that and my numbers were normal. It’s 30 bucks or so. Not worth every change, but certainly good piece of mind every now and then. Especially if you’re worried about a HG leak. The compression test with the blue fluid is not super accurate. The liquid may slightly change shade and you’ll run yourself crazy on whether or not it’s positive.
 
If the test is slightly positive, using a bars sealer might just stop it from progressing vs waiting until it is too large to plug.
There shouldnt be any coolant in the oil.
 
simple said:
On one of my oil analyses I did they found a high concentration of potassium which lead them to believe it was coolant in the oil and I may have a HG leak. It was right after I had my water pump changed. I don’t know why or how coolant got into the oil, but I have a 08 so HG isn’t common. I changed the oil again and got it checked and there was still a trace amount but much left. They said if I did the repair, it may just be a little residual. One more oil change after that and my numbers were normal. It’s 30 bucks or so. Not worth every change, but certainly good piece of mind every now and then. Especially if you’re worried about a HG leak. The compression test with the blue fluid is not super accurate. The liquid may slightly change shade and you’ll run yourself crazy on whether or not it’s positive.
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05 v6 210k miles at analysis, I had 50ppm potassium in my last oil analysis with some sodium (maybe 20ppm?) as well. The numbers are actually coming down compared to previous analyses, which is odd. I haven't done anything water pump, so I think its slight HG leak. Blackstone actually thought I fixed it based on the numbers, but I haven't done anything lol. What did your numbers look like?
 
Well this is good news. The test was negative for head gasket leaks. The fluid stayed blue after about 5 minutes of bubbling

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I bought the test kit so I will periodically recheck the engine. Im still wondering why I get white residue in the exhaust though.

Next step is to find out why I have a lean condition on Bank 2 drivers side. Maybe just needs new plenum gaskets and fuel injectors.
 
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Drcoffee said:
Well this is good news. The test was negative for head gasket leaks. The fluid stayed blue after about 5 minutes of bubbling

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I bought the test kit so I will periodically recheck the engine. Im still wondering why I get white residue in the exhaust though.

Next step is to find out why I have a lean condition on Bank 2 drivers side. Maybe just needs new plenum gaskets and fuel injectors.
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That test kit looks awesome. How lean is your bank 2? I've noticed that my LTFT on that bank is around 10% while the other bank is closer to 0%. I haven't been able to figure out why. I don't have a whistle like yours, but I also haven't tried to track down any vacuum leaks. I'm interested to hear what you find.
 
djpope09 said:
That test kit looks awesome. How lean is your bank 2? I've noticed that my LTFT on that bank is around 10% while the other bank is closer to 0%. I haven't been able to figure out why. I don't have a whistle like yours, but I also haven't tried to track down any vacuum leaks. I'm interested to hear what you find.
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My LTFT bank 2 is 7.81% and bank 1 is 0%. So it has to be at the intake or cylinder level. I was concerned that it was a head gasket leak affecting the fuel trims. So fuel injectors are cheap $30 ea rockauto reman. The gaskets are cheap $5 each. So the plan now is to pull the intake plenum and reseal the runners and replace injectors. The spark plugs are new and I switched the igniters from left to right with no change. Its not ignition related. I do have a p0446 large vac leak and from what I have read seems to be a charcoal canister seam leak. A lot of silicone or JB weld will be used and hopefully resolve that issue. The emissions leak would alter both banks LTFT so these must be different problems.

The test kit is a Lisle tool I bought at Advanced Auto parts. $42. It attaches to the vac port with a hose.
 
Long & Short Term Fuel Trim

Great subject with the head gasket and the approach to trouble shooting.
You mention the differences between bank 1 and 2. I'm very green interpreting this information. What exactly is this showing us?
 

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kc15842 said:
Great subject with the head gasket and the approach to trouble shooting.
You mention the differences between bank 1 and 2. I'm very green interpreting this information. What exactly is this showing us?
Click to expand...




What Fuel Trim Values Should Be
Ideally, the STFT and LTFT should be within a few percentage points of zero when the engine is idling or being held at a steady RPM. Remember, STFT can bounce around quite a bit as when you suddenly snap open the throttle or decelerate. But LTFT can tell you if the average fuel/mixture is running rich or lean.

Good LTFT values should be as close to zero as possible, though they can range from 5 to 8 percent depending on the condition of the engine. If the LTFT is getting up around 10 percent or higher, it usually indicates a problem that needs to be diagnosed.
 
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