MD93R1

Hello all,
I removed my air-box while trying to get to other parts of the engine bay and haven't had the chance to reinstall it yet. Can I start my car without the air-box installed (not drive) just want to start it to keep the engine running once a week or will there be bad things happening if I do that like throwing a engine code.
thanks..

jm2fd

The only problem with running the engine with no airbox is you'll be sucking dirt and dust into the engine, but if you're running it (and not driving it around) in a clean-ish environment with calm air you'll be mostly fine in that regard.

Sgtblue

iTrader: (16)

You'll be fine. The FD uses a Manifold Absolute Pressure (MAP) system and there's no sensor or meter in the intake tract like there is in the more common Mass Airflow (MAF) system. So no worries about any codes.

MD93R1

I went ahead and started the car with no problems (thanks for the help gents). I did notice another issue. After I shut the car down after letting it warm up for 15 minutes the hose at the top of the AST popped off. This has happened once before as well, the car never over heated, and I dont notice any coolant loss. I have some white smoke on start up but its gone within a minute. Do I need a new hose? or is there something worse going on?

Thanks

Sgtblue

iTrader: (16)

The small hose at the AST neck goes to the coolant over-flow tank. It doesn't need to be super-tight, but it shouldn't come off that easily. It's a thin walled hose that may have stretched out a little over the years. If that's the case re-install with an OEM pinch-clamp. Some coolant should be flowing into the tank through that hose when the engine is at operating temperature due to expansion. It's then sucked back out when the engine it shut off by the natural vacuum that occurrs as it cools. If you didn't see anything coming out of the nipple while running the car (a) it didn't get hot enough (b) you're low on coolant or (c) you may need a new cap.

jm2fd

I suspect you have a blockage in the line between the AST and the overflow tank. The system couldn't flow coolant out into the overflow like it should be able to, and it popped the line off instead. This is (or should be) a very, very low pressure operation. So unless the hose is sloppy loose on the AST nipple, you don't need a new hose or clamp.

You should be able to easily blow air through that line and hear the air gurgling in the overflow tank. If you can't blow into that tube you have a pinch or a blockage.

MD93R1

Thanks again everyone for the assist! Im going to check the coolant levels and will also try to blow into the hose, its loose but not sloppy loose. If i do have a blockage, should I replace the hose, is the hose even sold separately? Or am I better off just replacing the AST along with the hose? The AST is old, installed in 2002, but since then the car only had 17k put on it. Same goes for my engine im hoping the coolant or oil seals arent bad, I guess I will find out once I do a compression test. What are the odds things are bad considering the low mileage after the rebuild though it was a long time ago. Do seals go bad just from age?

Sgtblue

iTrader: (16)

If that coolant over-flow hose isn't plugged or pinched, and it's not otherwise leaking, I wouldn't mess with it. Just secure it to the AST. If the AST was replaced NEW in 2002, then it's probably one that was supposedly strengthened over those produced earlier and installed on cars in the 90's. Still, if it were me, I'd replace it when I could with a quality all-metal version or delete it.
Technically, seals don't go bad with age, but coolant does. Coolant gets acidic with time and electrolysis happens. THAT could be hard on them. If you haven't yet, flush and replace the coolant ASAP. For more efficient cooling, use as much distilled water to coolant as you can for your climate.

MD93R1

Im going to go ahead and replace the AST. I noticed pettit makes one, any recommendations appreciated. I couldnt tell if the hose is blocked or not, although when I blew into it, I didnt hear any bubbling in the overflow tank. So that means coolant is low as well or the hose is blocked up. I read there is a check valve on the hose? is it potentially blocked? Im going to pull the hose off completely and try to see if it can be cleared. Hey thanks again guys for answering the noob questions.

otto914

my 93 has a hose on the airbox that goes down by the inter cooler and is open. connected to nothing. is that okay and if so whats it for?

Sgtblue

iTrader: (16)

Yes. The factory blow-off valve empties into the airbox. It's simply a vent hose for the positive pressure. Normal.

otto914

thank u first response ive got in these forums what if u break the tabs off ur bottom air box

Sgtblue

iTrader: (16)

^That's another common issue. Those 'loops' break. When I was still using the stock airbox I think one was gone on mine. You can either fab something up on the box you have, or watch the "Parts for Sale" in the 3rd Gen. section. They come up occasionally. Not sure if there's a minimum post requirement, but you might be able to put up a 'Want to Buy" thread there.