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Coolant Leak???

5K views 12 replies 5 participants last post by  DigitalGT 
#1 ·
I have a decent coolant leak on my 125k mile SVTF. The coolant is running down and dripping off the bottom of the transmission. I can see any leaks from the top of the engine. Anybody have any ideas where the coolant might be coming from on the bottom half of the engine? Thanks for the input, Nate.
 
#4 ·
More than likely Nate all you need is a new o-ring. You can replace it with a Ford item and just be prepared to replace it again later or upgrade to a Viton o-ring. Steve at Tousley knows the part number off the top of his head by now I'll bet.

If you sneaky and work on a cold motor you can unbolt the housing from the block, pull the ring out, stick a new one in and reinstall the housing without disconnecting anything. You'll just need to top up the coolant afterwards.
 
#5 ·
I have searched everywhere but have not been able to come up with any pictures of this leaking plug/o-ring. Does anybody have a detailed step-by-step? Thanks, Nate.
 
#6 ·
If i recall i dont think ford sells the o-rings by itself but i might be mistaking. My housing started leaking from the main opening into the head and the little silver nub fitting on bottom of housing. If you do decide to change housing, make sure you reuse the clips for the sensor and the fitting on the bottom.

Here is what steve sent me for around $80 if i recall. Easy swap in about 30-45min. You cant replace the seal in the housing opening (pic). And the fitting on the bottom which tends to leak also is whats pictured on the right in the bag. Hope this helps

 
#7 ·
It is likely the o ring.

There is an opening on the bottom of the housing. You can see the opening on the top of the picture on the post above. It is the part that you see with a "slot". The slot is where a U clip goes. There is a metal plug in the opening/hole in the housing and the plug is held in by the clip. You will pull the clip off towards the front of the car and pull the plug out of the hole. In the picture above I believe the plug is the silver item with an O ring on it.

The "O" ring is difficult to remove and replace. You will need strong fingers and a very small flat tip screw driver to get it done. Meanwhile the coolant will leak onto the ground and you will be laying in it to put the plug back in. the plug will not want to fit back in and you will have to drive it back in with a drift and hammer. Then make sure the plug is completly in/seated, and replace the clip. Fill with coolant. wash up the mess. have a beer.
If you used the standard Ford item, be ready to do again in 2-3 years.

Like posted elswhere, use an O ring with better material. The temperature climbs when the engine is shut off, and the factory O ring deteriorates.

PS there is NO....obvious reason for this opening. Seems like a complete screw job for the car owner. :thumbdown:
 
#9 ·
I believe it's there as a port for a second water temp sensor. Some Ford cars have two water temp senders, one for the ECU and one for the gauge. Some Mazdas have this too, like the MX-6 V-6 / Ford Probe GT, 626, and MX-3 V-6 (all essentially the same car with different motor sizes).

Keep in mind the 2.0 Zetec is a stroked version of the regular Euro Zetecs. They may have different stuff over seas that necessitated a second stat housing port. It's cheaper to design, mold, and produce one housing and toss in a sealing plug than it is to make two separate housings.

It could also be a parts bin item that was designed for something else but lent itself well to the Zetec. Who knows. One thing is for sure, Ford didn't just put the extra port there on a whim. It has a purpose, just not for our application.
 
#10 ·
My engine is out of the car so I just went and checked my stat housing because I was curious.

The second port with the aluminum sealing plug is definitely for a second coolant temp sensor. I just pulled the temp sensor and the plug out and they interchange from port to port. The plug is also machined to resemble the temp sensor.

That got me to thinking. Some of the Euro Mk1 Foci had digital climate control. I wonder if that port was for a second coolant temp sensor on those models.

I know little about the Focus RS. Perhaps it's a coolant feed for the RS' turbo? Doubtful though.
 
#11 ·
DigitalGT said:
My engine is out of the car so I just went and checked my stat housing because I was curious.

The second port with the aluminum sealing plug is definitely for a second coolant temp sensor. I just pulled the temp sensor and the plug out and they interchange from port to port. The plug is also machined to resemble the temp sensor.

That got me to thinking. Some of the Euro Mk1 Foci had digital climate control. I wonder if that port was for a second coolant temp sensor on those models.

I know little about the Focus RS. Perhaps it's a coolant feed for the RS' turbo? Doubtful though.
Good thinking on that one. I would have never guessed.
 
#12 ·
What would stop me from removing the housing to install the plug from the top of the engine? Seems like it would be easier. I could use a clamp to force the plug back in. Nate
 
#13 ·
Nothing would stop you except the length of the coolant temp sensor harness.

You won't need a clamp to install the plug. Once the metal clip has been pulled off, you can pull the plug out and install it fairly easily.
 
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