My 2003 V8 started smelling bad in the engine bay after long trips. There are no fluids leaking on the ground, but I took the skid plates off and noticed some oil leaks on both heads. Can you tell if this is the head cover gasket? Head gasket? There's also a fair amount of fluid on the power steering pump, but to me it looks like oil rather than ATF fluid. Thanks for any help or tips to identify the source.
Help identifying leaks
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mikewhiskey
New member
This is interesting. The smell (and I assume oil leaks) started a few weeks after I did my last oil change in Nov which coincidentally is the first time I've ever used full synthetic oil in it. We've all heard about issues with synthetic oil causing leaks, but I read those were debunked. Looking now, those busted myths seem to be on the oil manufacturer's sites. 
Or perhaps I got a mislabeled jug with the wrong weight oil. It's awfully coincidental for both valve covers to be leaking that much and me to have not noticed it before.
I think I'll clean off the leaks and put some dino oil in and see what happens. It's still showing nearly 100% full since Nov. so not much has actually leaked out.
I know I'll be judged harshly, but I used Walmart brand high mileage full synthetic: https://www.walmart.com/ip/Super-Tech-High-Mileage-Syn-5w-30-Qt-Dx/764492025
Or perhaps I got a mislabeled jug with the wrong weight oil. It's awfully coincidental for both valve covers to be leaking that much and me to have not noticed it before.I think I'll clean off the leaks and put some dino oil in and see what happens. It's still showing nearly 100% full since Nov. so not much has actually leaked out.
I know I'll be judged harshly, but I used Walmart brand high mileage full synthetic: https://www.walmart.com/ip/Super-Tech-High-Mileage-Syn-5w-30-Qt-Dx/764492025
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smokey73
New member
+2
And it's been my experience that if you switch to synthetic on a high mileage engine, you'll never stop all the leaks. I did the same thing on mine at 250k. Oil started leaking from everywhere. I chased leaks for months. I finally switched back to conventional oil and now it's as dry as a bone. You might also check the PVC valve, make sure it's not stuck.
Inv4drZm
Senior Member
How many miles do you have on it now?
I wouldn't really consider any Toyota motor under 200k as high mileage. I wouldn't expect any 'high mileage' motor oil to have any benefits in these motors though I don't know how they work exactly.
Heck 'high mileage' is probably closer to 500k with the 2UZ.
AuSeeker
Elite Member
Have you checked to see if the valve cover bolts are tight, as in at the proper torque?
I ask this because I always check bolts and nuts for being loose periodically, and also I know that my valve cover bolts were loose when I bought my T4R and it had signs of slightly leaking at the valve covers, after thighening them no more signs of any leaking, I also use a synthentic oil since I bought it and the oil that was in it was not, and I changed my oil at around 6000 to 7500 miles and it's has always been on full when I do change the oil.
I ask this because I always check bolts and nuts for being loose periodically, and also I know that my valve cover bolts were loose when I bought my T4R and it had signs of slightly leaking at the valve covers, after thighening them no more signs of any leaking, I also use a synthentic oil since I bought it and the oil that was in it was not, and I changed my oil at around 6000 to 7500 miles and it's has always been on full when I do change the oil.
That_Titanium_4RNR
New member
Story Time
A few months into owning my prior vehicle which was a 2001 Chevrolet Silverado I decided I wanted to do the "right thing" when changing my oil by running synthetic. TERRIBLE MISTAKE....let me say it again....TERRIBLE MISTAKE. Never again will I run synthetic on a vehicle with over 170k if the previous owner was using conventional. I bought my truck at 199k and it was in incredible condition mind you...those who are familiar with these trucks know that they can have a myriad of issues. Mainly where I am these issues are things like rust in the rockers and cab corners, intake manifold leaks, and exhaust manifold leaks. Mine was perfect and was immaculate inside and out. Not a spec of rust, no oil leakage whatsoever, and the engine ran perfectly.
I changed that oil to synthetic and immediately I had massive oil leaks occurring. Everytime I started/drove the truck I would lose approx. 1/2-1 quarts of oil within a matter of minutes it seemed. I was losing oil from the rear main, oil pan, and valve covers. I then took it to my mechanic that day who went to work on it. 900 dollars later and my truck was spotless again. But I had learned my lesson. Let this be a warning to all who think synthetic is a good idea on an old vehicle that has only ever ran conventional...DONT DO IT. it is simply not worth the issues in my opinion just for that extra piece of mind that we get from using synthetic.
A few months into owning my prior vehicle which was a 2001 Chevrolet Silverado I decided I wanted to do the "right thing" when changing my oil by running synthetic. TERRIBLE MISTAKE....let me say it again....TERRIBLE MISTAKE. Never again will I run synthetic on a vehicle with over 170k if the previous owner was using conventional. I bought my truck at 199k and it was in incredible condition mind you...those who are familiar with these trucks know that they can have a myriad of issues. Mainly where I am these issues are things like rust in the rockers and cab corners, intake manifold leaks, and exhaust manifold leaks. Mine was perfect and was immaculate inside and out. Not a spec of rust, no oil leakage whatsoever, and the engine ran perfectly.
I changed that oil to synthetic and immediately I had massive oil leaks occurring. Everytime I started/drove the truck I would lose approx. 1/2-1 quarts of oil within a matter of minutes it seemed. I was losing oil from the rear main, oil pan, and valve covers. I then took it to my mechanic that day who went to work on it. 900 dollars later and my truck was spotless again. But I had learned my lesson. Let this be a warning to all who think synthetic is a good idea on an old vehicle that has only ever ran conventional...DONT DO IT. it is simply not worth the issues in my opinion just for that extra piece of mind that we get from using synthetic.
I even looked at a bunch of "oil" sites with this:
This is frankly BS. My engine had no leaks, so one could assume the seals and gaskets were in good condition.
I also have a coworker with an old GMC that's leaking a quart a month, and he didn't correlate it to the switch to "high mileage synthetic" until I told him my story.
Myth #3: Synthetic engine oils can wear down seals in an engine and cause leaks.
This is an often-cited myth. In fact, if your seals and gaskets are in good condition, synthetic oil will not leak in your engine. Synthetic oil has not been shown to deteriorate engine seals or gaskets. But it might find an existing leak. The smaller molecules of synthetic oil are able to pass through very small cracks and crevices that the larger molecules of petroleum-based oil cannot. Eventually, those small cracks and crevices can lead to bigger problems — with or without synthetic oil.
This is an often-cited myth. In fact, if your seals and gaskets are in good condition, synthetic oil will not leak in your engine. Synthetic oil has not been shown to deteriorate engine seals or gaskets. But it might find an existing leak. The smaller molecules of synthetic oil are able to pass through very small cracks and crevices that the larger molecules of petroleum-based oil cannot. Eventually, those small cracks and crevices can lead to bigger problems — with or without synthetic oil.
This is frankly BS. My engine had no leaks, so one could assume the seals and gaskets were in good condition.
I also have a coworker with an old GMC that's leaking a quart a month, and he didn't correlate it to the switch to "high mileage synthetic" until I told him my story.
08TxRunner
Member
So what exactly is the theory behind synthetics causing leaks?
Various oil companies have this on their website.
Myth #3: Synthetic engine oils can wear down seals in an engine and cause leaks.
This is an often-cited myth. In fact, if your seals and gaskets are in good condition, synthetic oil will not leak in your engine. Synthetic oil has not been shown to deteriorate engine seals or gaskets. But it might find an existing leak. The smaller molecules of synthetic oil are able to pass through very small cracks and crevices that the larger molecules of petroleum-based oil cannot. Eventually, those small cracks and crevices can lead to bigger problems — with or without synthetic oil.
Myth #3: Synthetic engine oils can wear down seals in an engine and cause leaks.
This is an often-cited myth. In fact, if your seals and gaskets are in good condition, synthetic oil will not leak in your engine. Synthetic oil has not been shown to deteriorate engine seals or gaskets. But it might find an existing leak. The smaller molecules of synthetic oil are able to pass through very small cracks and crevices that the larger molecules of petroleum-based oil cannot. Eventually, those small cracks and crevices can lead to bigger problems — with or without synthetic oil.
