(This story was originally posted on 12/28/2017 and has been updated. Please see bottom for updates. - Ed.)
The Ford Focus RS is America's first RS and the most powerful version of the hatch that has ever been offered. Enthusiasts who wanted an RS for years but could never get one snatched the car up at the first opportunity. Some of those buyers just wanted a quick daily driver, while others took them right to the track. But, like other first year performance cars, there were issues that popped up.
The most notable issue shared in owners groups and on forums . While there has been some speculation on the underlying issues, there hasn’t been an official answer from Ford. We dug into Ford's service information and patents to find out why so many of these cars have blown head gaskets.
One of many threads on the FocusRS.org forums links to a spreadsheet that with the problem. They vary from completely stock to heavily modified, but the majority of them appear to be early builds from April to July of 2016, with a few later builds sprinkled in towards the end. The issue usually presents itself with an engine that starts to run rough or when white smoke appears out of the exhaust, caused by coolant entering the combustion chamber.
Many theories on the root cause have popped up but it may all come down to an incorrectly delivered gasket. Many Focus RS owners have posted pictures of their failed head gaskets and the design appears to match the gaskets found on the Mustang 2.3L EcoBoost. While the two engines share many components and specifications, the cooling passages in the RS are different from those found in the Mustang.
The Mustang uses a small v-shaped passage cut into the block between the cylinders in order to transfer coolant across, as shown in the image above. There are two connected holes in the gasket which can accept coolant and transfer it all the way to the edge, at which point it can flow into the water jacket. These holes can be seen in the image below, which was pulled from Ford’s online service information website.
The block in the Focus RS is slightly different as it does not have this passage cut into the cylinder block. Instead, the coolant is routed through a passage that is drilled below the deck surface. This type of design only requires one hole on top to connect it to the cylinder head. That's because the other hole comes in from the side and below the deck. Ford on this design. It explains that coolant enters adjacent to the block (132 on the diagram) and exits from the top of the deck (178 on the diagram).
Moving one of the coolant entry points from the top of the deck to the side and skipping the v-groove necessitates a change in the head gasket as the second hole and passage in-between is no longer required. Removing the second hole and the bridge in the gasket prevents coolant from seeping into the area between the fire rings where the v-shaped groove would exist on the Mustang block. Since there is no groove there to allow the coolant to circulate back into the block, it gets stuck in the passageway where it can boil and eventually damage the gasket. I've illustrated the area where the coolant would get trapped in red on the patent illustration below.
This head gasket change to one hole can be seen in the service information for the Focus RS and in images of the current Focus RS gasket online. It does not appear in any of the failed head gasket images. Ford even noted that the head gasket has been modified . This leads me to believe that Mustang head gaskets were incorrectly installed on some Focus RS engines.
One reason that the incorrect gaskets may have been installed is as a cost saving measure. However, I find it unlikely that Ford would cut costs there, particularly because the company took the time to redesign the coolant passages in the block. My theory is that both gaskets come from the same supplier and are made on the same lines since they are so similar. It is possible that a supplier incorrectly sent some Mustang gaskets for a run of Focus RSes and, since they physically fit on the block, it was never noticed that they were not correct.
Although we’ve seen a few stories on the subject and a lot of activity on the forums, I do not believe that the issue is widespread because Ford has not sent any type of bulletin or notification to their technicians at this time. We asked them to confirm our findings and let us know if there is a bulletin or recall on the way but they only shared the following statement:
Ford is aware that some 2016-17 Focus RS customers have experienced concerns with their engines, which may initially show white exhaust smoke and/or coolant consumption. We are working on a repair for all customers that will be available in the near future. In the meantime, if vehicles show these symptoms, customers should visit their dealer for an inspection and repair under warranty.
Ford seems to be taking care of the issue and is replacing the gasket, head, and even entire motors as necessary. According to some reports, Ford is a little behind as some cars have been sitting at dealers for weeks waiting on new head gaskets to arrive. Hopefully, it is able to share more information with us soon and confirm the misplaced gaskets so that owners can be at ease to enjoy their cars.
Update: New info gleaned from readers and forum posters:
We've received additional information since we published the story and the latest included an explanation of Ford engineering and service part numbers. The engineering part number is one that is used on the manufacturing side and is often stamped into the part. The service part number is the one that is published in parts catalogs and used to order the part after it is produced.
According to the spreadsheets we received, the engineering part number for the Mustang, MKC, and Explorer head gaskets is EJ7E-6051-xx, while the service part number is EJ7Z-6051-x, where x represents incrementally changing letters for each revision.
On the other hand, the engineering part number for the Focus RS head gasket is G1FY-6051-xx, while the service part number is G1FZ-6051-x.
We were shown a copy of one parts spreadsheet that states that the 2015 Mustang head gasket had an engineering part number of EJ7E-6051-GA with a service part number of EJ7Z-6051-A as of March 2015. The Focus RS is listed as having an engineering part number of G1FY-6051-UB, with a service part number of G1FZ-6051-C as of January 2016 on that same spreadsheet.
A tweet from a Ford parts employee also confirmed that the EJ7E-6051-HA engineering number pulled out of a Focus RS is to the Explorer and MKC engine in the parts catalog.
This reinforces our earlier claim on the incorrect gasket being installed. According to the parts employee, the correct current gasket for the Focus RS should have G1FY-6051-UB stamped into it.
Reader Alex Durant also sent in the following info:
Some pictures from Focus RS head gasket failure, you can see the difference between old gasket and new (Mustang vs Focus RS) also you can see the side drilled cooling passage mentioned in the article. Those pictures are fromtime they replaced my head gasket, so either they replaced one with another Mustang one, or they updated the head gasket (which is what the dealer told me).