Please help diagnose: LIM O Rings?
 

Ive got a slow coolant leak causing two puddles on top of my lower intake manifold between the housing and lim. I'm pretty sure this is O Rings but I just wanted a second opinion before I start ordering up replacement intake gaskets. I dont seem to have any other sings of leaks except below the lower intake manifold on the rear housing, also looking like O Rings. I did get the engine a little bit hotter than I would have liked (About 215) but it never blew a hose or anything. No bubbles observed in coolant while engine started, no misty sweet smell out the tail, nothing sweet tasting in the oil.

Please take a look at these pics of the LIM/Front housing where the coolan is pooling. These dimples when starting out completely dry fil up after about 30 minutes of driving normal speeds.

Thank you

Before ripping all that apart, check the coolant hoses that run under there...

There's the front one that normally runs from the back of the water pump housing into the BAC valve.
Then there's the rear one that runs from the top of the rear iron into the TB.

In fact, I put money it's either one.
If the LIM o-rings leak, the coolant normally gets sucked into the engine.


-Ted

man... everything else looks so very dry under there, even the rear housing doesnt have a pool of coolant like this front one.

that hose i told ya bout, maybe a bad seal with ur thermostat housing or a crack in it. and that hose behind the water pump housing the dude mentioed above

Thermostat housing gasket (or o- ring depending on year)

Leaking BAC coolant hose stub.

Leaking temp sending unit, I know about this first hand. When I had my water pump housing out so I could drill and tap a hole for my after market temp gauge I pulled the sensor so I could work without damaging it. When I put it back I only hand tightened it. Took a bit of time to figure out where the leak was coming from since I only was seeing a very small amount of coolant. .

Take your time and you WILL find the problem spot.

Even money its the BAC hose stub or the sender. :icon_tup:


Thought I'd add this quote Mazdatrix and the link to that page as well.

http://www.mazdatrix.com/b9.htm

89-95
Note: We have had several problems lately with the
OEM 89-95 thermostats due to their rubber seal failing.
For this reason, we sell the Stant thermostat for this application.

Thermostat housing gasket (or o- ring depending on year)

Leaking BAC coolant hose stub.

Leaking temp sending unit, I know about this first hand. When I had my water pump housing out so I could drill and tap a hole for my after market temp gauge I pulled the sensor so I could work without damaging it. When I put it back I only hand tightened it. Took a bit of time to figure out where the leak was coming from since I only was seeing a very small amount of coolant. .

Take your time and you WILL find the problem spot.

Even money its the BAC hose stub or the sender. :icon_tup:

man.. all those areas are dry. I just took off both the upper and lower intake manifold. Why does my engine not have orings installed at all? The housings dont appear to have any passages under there.

This just sux. its al apart and I have no clue. Everything on the waterpump is dry as a bone with no sign of leaks. Man this is realy pissing me off like crazy.

i was gonna say, i bet there are no orings :)
i guess i was right, time for some orings!

haha, no coolant passages?
You're either running non-turbo or FD rotor housings... :)


-Ted

if there are no passages and there is still coolant in the manifold, then its comming up thru the turbo inot the manifold and leaks where the orings would be. so check the other side of the coolant line on the turbo

I had that happen once when I forgetfully omitted the o-rings from the install.

I had RTV'd the gasket with a slight film and the film was enough to hold coolant there without pressure (ie.e when I filled it up and looked for drips etc.) but once it ran the cavities you have in the pic would fill with coolant.

That may be the case. This engine was rebuilt with an Atkins kit about 25,000 miles ago. I think at least one rotor housing ware replaced. That being said, there is no passage where ORings should be.

Well this may be the case, but, my turbo is actually NOT water cooled. The lower water pump nipple is also plugged. If it was water cooled, wouldnt coolant flow from the front housing to turbo to lower water pump? Again, the passage from the rotor housing seems to be plugged and non-passable.

I cleaned the pools of coolant before pulling the lim off. Got it off and there was coolant all over the place: the lim to engine gasket was soaked with coolant. There was even traces of the green stuff on the intake runners and even slight amounts inside the engine's intake passages, although I never noticed anything puffing out the tail pipe.

Also, my car is not running with a BAC. It does have the thermo valve/cold/high/idle but all that is dry. Rear of water pump:dry. Rear housing to thermo valve: dry.

:(


Tonight I plan on pumping .9 bar of pressure on the cooling system and see what leaks on this freakin bizzatch.

I'll take a few photos tonight

Well it looks like we ALL were wrong about this.

Just found my leak after pushing 10psi of compressed air into the system:

Its leaking coolant from the very top of the front cover, where the front cover bolts to the front iron. Looks like the gasket/rtv blew out right there.

I'm glad I dont have to break the motor appart, but I sure hope removing this cover isnt a pita!!!

I'm actually quite happy about this :)

coolant travels through the front cover?

You are right it was just water pump gaskets. Its been awhile since I've really worked deep in these engines. My water pump was missing both front and rear gaskets; it was just silicon rtv which blew out easily in the gasket's place.

Quick fix, just need the gaskets and a few other worn out parts.

Thanks all!!!

Just found out that my engine was rebuilt with two rear S5 T2 rotor housings... I wonder what else might be affected by this. Hmm.