Rx7isthebest

After just unflooding my engine and getting it to start just fine, this is what happens...

I'm driving along and I notice a power loss. Even at WOT there wasn't much power at all. A couple minutes later, I see smoke/steam coming from the engine. I immediately stop and coolant is splashing all over the ground and engine bay. It was pretty obvious it was the AST causing the massive coolant loss. I taped up the leaking sections of the AST and added coolant until the add coolant light went away. I tried driving and after 5 minutes the add coolant light came on again. I repeated the same procedure and yet again I had to stop because the engine got hot. At this point, I had my friend tow me home with his truck.

Should I even bother replacing the AST or is it rebuild time? The engine starts up just fine but why the loss of power? Could a really hot motor be the cause of the power loss?

Thanks a lot!

dgeesaman

iTrader: (7)

Quit trying to cheap-rig it and fix that AST!! Don't drive it!! For crying out loud, you can get a low mileage one for $20 on the for sale forum, an AST elimination kit for $50, or a used aluminum AST for not much more. I don't know why you're wondering if you should replace the AST, considering that you will need one anyway if you got the engine rebuilt also.

Do you have a water temp gauge? How hot did it get? Put on some sort of good AST, go to Autozone and borrow their coolant pressure tester and test the system. If it leaks some, pull the plugs and see if the coolant is going into the chambers. If it holds pressure overnight, take it for a drive and see if it's back to normal. Loss of power is very much a secondary issue until that's all taken care of.

Dave

djantlive

1. Get new AST (stock, alum). Don't buy a used one as they are prone to break.
2. Test compression to determine the engine condition.
3. Never drive car when you have a leak in cooling system -- Air goes in and air bubble doesn't cool engine, engine overheats and game over. Instead, buy the parts and fix the car on the spot or get the car flattrucked to a shop.

jic

iTrader: (1)

im the paranoid type so i replaced everything after i bought the car.
the only thing right now i have issues with is a radiator leak
but changing the stock ast to an aluminum one is pretty important.
ive never imagine it would break that bad, i just got it simply because it dont want it to leak

dgeesaman

iTrader: (7)

Compression tests work for apex seal breakage or very bad o-ring damage. To effectively test all ranges of coolant seal failure or block warpage, you need to do a coolant system pressure test.

Dave

jpandes

Good luck with this. I just hope that you didn't cook your coolant seals already.

Rx7isthebest

Thanks for your replies! Been busy and haven't been able to be on. I will follow yoru suggestions and update!

Rx7isthebest

I installed the pettit aluminum AST and now the system is holding coolant. I am still experiencing loss of power. The car just will just not boost properly. When it hits the boost range, I hear a loud rush of air coming from the engine bay. This makes me think that a vaccum hose got cooked or blown off from the heat? I think I'll get a compression test done...

Any suggestions/comments?

POS7

^^^ loud rush of air sounds like boost leak. Your car may have multiple problems/maintenance issues that you are neglecting.

Not critisizing (sp?), just making an observation

dgeesaman

iTrader: (7)

Big boost leak sound is usually a torn coupler.

Buy a boost gauge while you're removing and checking the 3" couplers for tears. Turn them inside out - the smallest slit will open up and leak air under pressure.

Dave

93Efini

i was having boost problems just recently, after removing stuff from the engine bay today and doing a little work i noticed the lower intercooler charge pipe (stock rubber pos) had a 3" tear in it.

if your running the stock intercooler and piping you might want to check that good, just an idea

Mike M

I have had the same experience with coolant flooding out of the engine bay: all of it. It was traced to a turbo coolant hose, repaired, and all is well with good compression and no leak. I had all coolanmt hoses replaced and a new AST tank installed.

Mike M

I have had the same experience with coolant flooding out of the engine bay: all of it. It was traced to a turbo coolant hose, repaired, and all is well with good compression and no leak. I had all coolant hoses replaced and a new AST tank installed.

POS7

Get a boost guage and water temp guage. These are important in diagnosing current and future problems regarding overheating and boost issues.

Get a downpipe if you havent already as well.

Rx7isthebest

The tube that connects to the Y-pipe coupler on top was very loose. I tightened up the coupler and now it runs a lot better but still not up to normal. I think it still may be leaking some air and I'm thinking about purchasing the Efini Y-pipe.