Question about combustion gas analyzer reading

Hello all, I hope someone has used one of these before and can tell me of their results. Lately, every once in a while I "think" I smell the faint smell of anti freeze right after I start the engine on my 05 V6 Runner. And over the course of 2000 miles since I replaced the water pump, etc. the level in the reservoir has dropped less than 1/2 an inch. So, I got a tester from Harbor Freight and tested it. The instructions with the tester said if the liquid turns yellow on gasoline engines or green on diesel engines, there is combustion gas in the cooling system, meaning a likely blown head gasket. Well, when I did the test it did change color slightly, but not to yellow. It's more of a greenish blue color. So I retested and got the same result. Not satisfied with this result I decided to go a step further. I took the tester to the tailpipe and let it test some real combustion gasses. When I did this it turned a nice yellow color. So now I don't know what to do. It didn't turn yellow while testing the radiator, (twice) but it did change color slightly. Does anyone know if that's considered normal? I'd also like to add that I have absolutely NO other symptoms of a head gasket failure besides the possible occasional smell and the very small loss of coolant. It never skips when first started. It runs near perfect. The temperature gauge runs below 1/2 way. Never goes any higher, regardless of the conditions or the ambient temp. It has 303K on it and I've had it since it had 263K so I don't know if it's ever had the head gaskets replaced. I suspect not but have no way of verifying that. So, can anyone share their results with this test or offer any advice on this. My plan is to just continue to monitor it until/unless something more happens. Thanks in advance for any help.

 

Dont have any experience with the tester so cant help you there, sorry. However almighty google shows that there are similar failed headgasket issues reported on the 03-05 V6 between Toyota120, T4R.org, ExpeditionPortal, and this site. Maybe one of them can help. Of note, on T4R, @BlackWorksInc is a Toyota mechanic and has some thread responses that are very pertinent-use your search function.

Stepping back, if you're at 303k miles and dont know if its ever been touched, I would not play the waiting game to see if yours continues to function. Personally I would tear into it myself or take it to a trusted shop to replace (there is an updated version of the gasket fyi) as soon as I could. Toyota is renowned for their longevity and reliability, but they aren't infallible...

 

Hey, iamincrediboy, thanks for the response. Yeah, I'm aware of the known failures from 03-05. I think if not for that I wouldn't even have bought the tester and checked it. I am an ASE Master Tech so I can certainly do the job myself. I just don't want to, lol. I'm 62 years old with rheumatoid arthritis and I'm now an auto tech instructor. Not sure how well my old aching body will do on a big job like this. And. like I said, it runs perfect, never misfires on startup like many head gasket failures, no mixing with oil, no steam from tailpipe. And while warming it up to do the test, the coolant never tried to come out of the radiator neck, (I had the cap off). And I frequently drive it for 5-6 hours straight at 70+ miles per hour and the temp never even gets to halfway on the gauge. My only concern is that I THINK I smell anti freeze once in a while after startup. And it lost a very small amount of coolant over a month's time driving about 2K miles. (less than 1/2 inch drop in reservoir). I just wish the test would have been conclusive. Thanks again for your response. I do appreciate it.

 

Sounds to me like HG failed. Do you see coolant disappearing? White smoke out the exhaust?

Could be a small drip into 1 cylinder. Try Blue Devil HG repair. Might work on a small leak.

Some have gone 3 years with BD!

How to Install BlueDevil Pour-N-Go Head Gasket Sealer - Bing video

(3) Reach for BlueDevil Products - Bing video

 

He is replacing the head gaskets & did not use a band aid sealer.

https://www.4runners.com/threads/replace-the-head-gaskets-or-replace-the-engine.20314/

 

Still a good idea to try BD before the HG replacement. Especially if your funds are stressed.

Head Gasket Sealer | Head Gasket Sealant | BlueDevil (gobdp.com)

I've read of Toyotas lasting an additional 3 years with BD.

My 2005 with 160,000 miles has no HG issues. I monitor it by watching the coolant overflow catch tank. If the coolant disappears, I know I got a problem.

Easy enough, as I'm always popping the hood to look at the engine, battery, etc.

Check the radiator cap for oil mix floating there too. So far, so good!

I'd definitely try BD if I had a HG issue on my 15-year-old runner.

Starts and runs like new currently.

 

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Never follow @captsolo's advice. If it is a head gasket issue, replace the head gaskets...don't ruin your engine with any band-aid solution suggested by @captsolo

 

Since your engine only has a finite supply of coolant, the easiest way to check is to monitor the level in the overflow tank and see if it is going down.

you said you lost some already, see if you lose some more.

I’m sure you’re aware that the level will fluctuate based on the temperature of the engine.