derSchwamm

iTrader: (1)

I put an S5 block in my FB last year and ran it with the GSL-SE electronics, ignition, etc. but I've had trouble getting it to run well (running rich). Because of this I've only put about 400 miles on it since last year, and it's been parked for the past couple weeks. I went out and started it today and saw a huge cloud of white smoke. It kept spewing a steady stream of smoke for a couple minutes before stopping completely. I've only ever seen this much smoke from an RX7 when my FD had a bad coolant seal.

This video is 30-60s after starting and is not the worst of the smoke:

I borrowed a universal coolant pressure tester which is just a long rubber cone that expands to seal in the top of the radiator and it doesn't seem to be holding pressure. I see a slow drop without leaks that I can see, and it dropped from 18psi to just over 16psi in an hour. I'm not sure what else it could be if it's not internal. I'll do a longer test tomorrow but it's not looking good. I think I saw some wetness on the front rotor's plugs but it's hard to tell with the crud on them from running rich.

Any other tests I should do before I take the engine out? Why would this happen in a fresh rebuild? I know it's my first one I've done, but I was meticulous. Not sure what I could have done wrong.

If it needs to be torn down, what new parts do I need to buy? New coolant seals obviously, but since the rest is almost brand new (apex seals, all O rings, springs, etc) I assume most can be reused

Dvst8

iTrader: (6)

The pressure test and coolant on the plugs is a sure sign its getting into the chambers. If not the coolant seal fail, maybe the coolant passages on the housings?

Barry Bordes

Two tests would probably be good.
The first would be put the pressure gauge radiator block off back on and allow it to go from 18 psi down to as low as it will go, pull the leading plugs out turn the engine over to witness how much water will come out... and which rotor.

The second test would be to run the engine with a radiator tester in place and witness whether the gauge increases while running.

Barry Bordes

Barry Bordes

Also a couple of tips on installing the cooling seals. They tend to run a little small so they can easily twist or jump out of the groove on assembly.

It is best to stretch them before installation......take one of your old harbor freight wood clamp that has broken, reverse the ends and use that to stretch the seals, when you find the correct distance describe a mark on the clamp for the next time.

Next make a pre-build stack of housings and plates using hylomar to adhere the seals in the grooves . I usually allow that to dry for a day.

You can then inspect the seals and make sure that they are going to be in the right position for an easy final assembly .
Barry

derSchwamm

iTrader: (1)

I'd heard seals like to jump out but it must have done so right at the last second, as the housing was getting stacked. I used Hylomar and assembled it quickly before the hylomar had a chance to dry. So there's nothing wrong with letting it dry like that? I also did not stretch them, but managed to get them in the grooves with a little work.

It's funny you mention a broken harbor freight wood clamp because of course I have one of those in my garage

Lastly... anything wrong with Atkins coolant seals? Forum results are a mix of folks saying their fine, and others saying use OEM. I used OEM the first time. Atkins sells a basic seal kit for $125 that I'm looking at using when I tear this down, reusing all apex seals, springs, side seals, main seals etc.

derSchwamm

iTrader: (1)

I let it sit pressurized for about 10 hours today and it dropped from 19psi to 9psi. I cranked the engine for a second and then pulled leading plugs and found the plugs to be dry this time. When one was wet yesterday, it's possible the plug was just oily or dirty from the car running badly. At this point I am not 100% convinced it's in the engine. It's slow enough that it could be a leaky hose that I haven't yet spotted. With all the rain we've gotten it's hard to see a leak outside.

Can anyone recommend a place to purchase a coolant pressure tester that fits the FB or tell me what sort of size to look for? I am not convinced that this universal cone tester is 100% leak free especially at the slow rate mine is leaking.

I'm going to let the car sit overnight, and it'll probably have zero pressure by then. I'll turn it by hand with the plugs out again and see if I can get any coolant coming out the spark plug holes

KansasCityREPU

iTrader: (9)

https://www.pineappleracing.com/cool...estercspt.aspx

Barry Bordes

The Atkins seals are fine.

The reason I glue ahead of time is to make final stack more manageable. When we’re trying to lubricate some parts and keep somethings dry or glued, or vaseline on the seals things can get hectic.

I also use a reversed wood clamp to hold the eccentric shaft up to the proper distance for sliding on the middle plate.

when the radiator pressure goes down overnight I would not start the engine for fear of hydro-lock. I would take out the plugs and turn it by hand.
and turning it backwards would probably be a better bet for seeing water in the chamber...... Instead of pushing it out of the exhaust port back on the correct direction.
Barry

KansasCityREPU

iTrader: (9)

If it had a leak into the rotor chamber, I would expect a bunch of water. At least enough to validate its water/coolant. Might be handy to take the exhaust header off a run the test again.

derSchwamm

iTrader: (1)

Not a bad idea. I did turn the engine backwards last night so in theory coolant should have made it out the plug holes. It didn't. I shoved a rag under the top radiator hose at the radiator because I thought I saw a leak, and it was wet with coolant this morning. That may be my issue if I am lucky. It only dropped another 1psi last night, it seems to be stopping. Maybe it only leaks there under higher pressure. I'll tighten some of these connections and retest... hopefully with better results! The only thing it doesn't explain is the white smoke, but maybe that was just from it sitting for a while in cold weather

I saw the pressure tester above but would prefer something that can snap onto the radiator so I don't have to pull the water pump (and drain all the coolant).

KansasCityREPU

iTrader: (9)

At this point I'd say just monitor the coolant level and not worry too much about it. I've had a massive leak on an old engine and with my current engine I'm super paranoid about water leaks.

IRPerformance

iTrader: (41)

Either a coolant seal was pinched during the rebuild, a rotor housing is warped, or the seal retaining wall collapsed. Being that is started smoking 400 miles after the rebuild, a warped housing is likely. This is why it is very important to measure them during the inspection process. A final less likely culprit is a freeze plug inside the motor went.

Ta-Aikah

I'll add a little experience with the last thing IRPerformance said. Not sure if the s5 engine has these, but one of my freeze plugs had worked its way out just enough (On a fresh rebuild, <200 miles on it) to leak coolant past the intake gasket directly into the intake, thus plumes of smoke. Might pull the intake and check those

derSchwamm

iTrader: (1)

I let it sit again last night and it only dropped from 15 to 14psi this time, after I tightened a few hoses more. A rag I stuck under the top radiator inlet was a little wet with coolant again, so that could well be the source of my pressure loss.

I drove my FD for the first time in a while last night, and on startup I also got a ton of smoke, more than I am used to. And this car has a cat and runs well, unlike the FB. I think the near-freezing temperatures, rain, and near 100% humidity here in east Tennessee are causing this because I know the FD's engine is healthy. I'll let the FB sit for the rest of the day and then will check one last time for coolant in the housings tonight before I assume it's actually fine and move on. Thanks for all the advice here. With the smoke and pressure loss I thought for sure I'd lost a seal but I may yet get lucky

derSchwamm

iTrader: (1)

Yesterday I checked everything again after it sat pressurized for two days. Pressure is dropping very slowly now, and I can spot one small external leak. I put fresh plugs in the engine, turned it backwards a few rotations by hand, and checked the leading plugs. Both were completely dry. When I started the car up again, I got a lot of white smoke, but it wasn't much more than my FD this time. When it started misfiring (it's not running well right now..) I'd get a burst of somewhat darker smoke, which I assume is fuel since it's running rich.

I think when I got the first video I had the perfect combination of cold (30-35º) humid weather and a bunch of fuel sitting in the engine from when it stalled previously. If I continue to have coolant loss issues I'll post back with what I find.

Maybe I'm just not used to driving old cars that aren't full of emissions equipment!

Frogman

my car did that after it rained all night, probably humidity