TECHNICAL: The RTV Issue

 

When the 2022 Subaru BRZ and Toyota GR86 hit the US markets in its latest 2^nd generation skin, this was a car that wasn’t met with any pushback or 2^nd thoughts from enthusiasts. The styling and overall execution of the car was proper, and much more attractive. There were a few gripes from online rando’s complaining that Subaru should have made turbocharged STI version, but we all learned from the previous 9 years since the first-generation BRZ models, that the BRZ was a drivers’ car. One where skill superseded speed, where smoother = faster on weekend autocross and track events. Where the nimble chassis could allow itself to carry through the apexes rather than relying on massive brakes and aggressive pads to slow down faster brutes. With a curb weight of just over 2800 lbs., paired with a 6-sped close ratio manual transmission option and 228 HP out of the new 2.4-liter engine, you were meant to have fun in this car.

Yet during the first year of the release of the Subaru BRZ and the Toyota GR86, there have been reports of owners losing their engines with very low miles, and even during the break-in period. Although the numbers of lost engines were still low enough to be considered isolated, there was still much pause for consern. What is going on? Were the bearing clearances too tight from the factory?

One infamous example was where a customer lost the engine at just 1400 miles on their Toyota GR86. There was oil starvation causing the engine to spin a bearing. Toyota (allegedly) had a field technician go inspect the car, and they viewed their social media showing the car at a track day, and the warranty was denied. But it was the discovery during the engine tear down that there was an abundance of RTV silicone that was blocking the oil pickup tube.

 

 

WHAT IS RTV?

Also known as Room Temperature Vulcanizing silicone that is designed to seal and cure during room temperature. For any of us who do our own wrenching, we know darned well that we have a tube of the Permatex Ultra Black in the toolbox. It’s one of the main ingredients that we’ve got.

RTV is mainly used to seal oil pans, but it can be used on other engine components that are exposed to oil such as timing chain covers, and it can be used on water pump housings on other makes and models. When RTV cures, it has the consistency of a hard rubber. And most RTVs will be oil and water resistant among other potential chemicals. However, the problem is when excess RTV is used, which has been somewhat of a problematic case in the 2022+ BRZ and GR86 models.

 

 

THE BIG PROBLEM

The big problem is that on some models on the assembly line, too much RTV was used on the oil pan on various FA24D engines used in the 2022+ BRZ and GR86 models. As the oil pan is torqued down, the RTV will squeeze out of the sides which can be natural for many engine assemblies. However, the problem was too much overhang. RTV is meant to create a seal between metal surfaces and not be submerged in oil, so the oil along with countless heat cycles when the engine is running will cause that RTV overhand to break apart, and fall to the bottom of the oil pan.

And this is when the potentially scary stuff happens. The OEM oil pickup tube will suck in and collect the excess RTV where it will get caught in the filter screen, creating a blockage of oil. When the passage from the oil pickup tube is blocked enough, you will create oil starvation to the rod bearings and main bearings. When you have lost oil pressure, it’s too late, and you will need a new motor. Your engine’s main cap bearings (crankshaft bearings), and your rod bearings have very critical clearances (as an example from 0025” for most engines). Those clearances are the measurement of oil that is allowed to sandwich between your bearing and your connecting rod and main cap on the journals. If the clearances on those bearings are widened, or enlarged, this means that something bad is happening and you will immediately lose oil pressure. Those bearings in good working order with the right clearances will maintain the proper oil pressure.

Now this is how oil starvation loses a motor. You have your internal rotating assembly of your crankshaft, connecting rods, and pistons. All of which must be submerged in oil. If RTV is blocking the passage of the oil return tube feeding the rotating assembly of those internal components, then that means that you will not have the proper amount of oil lubrication, and you will go metal to metal. Meaning that your engine’s bearings won’t have enough oil to properly keep the bearings, and your crankshaft journals properly lubed with oil. When you don’t have enough oil to keep your bearings lubricated, metal will start to shave and flake off the journals, the bearings quickly lose their clearances which prevent them from staying in place, and eventually the bearings will spin with the connecting rod or with the main cap as the motor rotates. Aka spinning a bearing. At this stage, we have gone into full catastrophe mode, and metal shavings and glitter have consumed your oil, and has spread throughout the engine, relying on your oil filter to catch the big stuff before moving through your head.

At this point you will need a full engine rebuild where a machine shop will have to properly smooth out your crankshaft journals. If the damage is big enough, machine shops will add/machine new material onto your crankshaft journals, and they will issue new rod and main journal bearings in a different size, and both your engine and head will need to be thoroughly cleaned and hot tanked to remove any remaining metal material.

 

THESE ISSUES HASN’T AFFECTED ALL 2022+ BRZ AND GR86 MODELS

Compared to all the production models, there have been mainly isolated incidents in terms of cars blowing engines because of RTV. But it’s alarming because these are new vehicles, and independent shops and enthusiasts who wanted to take extra precautions have discovered an excessive amount of RTV that has protruded inside of the oil pan, where it can be subjected to coming apart from the road vibration and heat.

Now again, this issue hasn’t affected enough models to where both Subaru and Toyota haven’t issued a recall to fix the issue. There are thousands of second-generation BRZ and GR86 models that are on the road where they have driven tens of thousands of miles without any issues.

But the question on the back of your mind still exists. Is there oil that could potentially block the oil return tube? And how can I clean it myself?

 

 

 

 

HOW TO REPAIR THE ISSUE OR GIVE YOURSELF PEACE OF MIND

Now if you’re mechanically inclined enough with the right tools, you can do this yourself the next time you perform an oil change. However, it’s not that easy, especially if you don’t have a lift or a Quick Jack kit. The job can be done on regular jack stands, but it will be tight. After you have drained your oil, you will need to remove your exhaust manifold so you can get full access to the oil pan. Once the oil pan bolts are removed, use a proper oil pan removal tool and do not use a flathead screwdriver. Use something thin and flat so that you are not damaging the mating surface of the block and oil pan otherwise you will really have a leak to deal with.

When the oil pan is removed, you can inspect your oil return tube, remove and clean out any excess RTV, and you can remove any RTV from the oil pan itself as well as from any on the mating surfaces. You can go the extra mile and upgrade your pickup tube with an extra safeguard

Killer B Oil Pickup Pre Filter 2022+ BRZ/GR86

 

During assembly, it is very important that you use OEM RTV designed to properly seal your oil pan. And lay down a proper bead of RTV that will not over compress and squeeze out of the inside and outside of your oil pan.

 

 

FINAL WORD: YEAH, IF I OWNED ONE, I’D DO IT

Just for peace of mind. Especially if you track your BRZ or GR86 as your engine will run harder, your engine will stay in the upper RPM ranges, where oil lubrication really needs to do its job without any RTV blockages. Even after 3 years since the second-generation BRZ and GR86 hit the markets, owners in curiosity are still finding RTV in their pickup tubes as it’s one of those issues that can stay in the back of your mind as an owner. Now if you don’t have the tools or knowledge to perform this job yourself, it will be an easy job for any experienced mechanic with a lift. The hardest part will be removing the exhaust manifold. But a wise investment, especially if you plan on keeping your second-generation BRZ or GR86 for the long haul.