99 Impreza Engine Help/advice needed Dallas, Fort Worth

[SUBARU3]

  Hey guys:

 

      There is local young man near me here in Dallas, Fort Worth, TX and he needs some help with his car.

 

 Here's the situation. He has a 99 Impreza Outback Sport. (SOHC 2.2) It has 136 K on it and it seems to have developed, (suddenly) a  zero compression cylinder. The car starts and runs, but there is no compression in one cylinder. I'm not so sure that this may not be a complete external blow out of the head gasket, but I'm thinking it may be something in the head. (There is no significant metallic noise). There is no oil/coolant mixing anywhere. Your thoughts?

 

 The car is in nice shape and all other mechanical items are in good condition. (Tranny, brakes...bla, bla_). I suggested that he should just have the head pulled and inspect. You will know if it's the gasket right away. Then do the cylinder head work if it's a valve or something. I think the engine is worth repairing. Replacement would be significantly more and most likely much higher mileage too.

 

 Any thoughts on what this might be?

 

 Also, he needs to find somebody that knows Subarus in the Dallas, Ft Worth Area, or someone that could help him out. (I do not have the time or space)  He had the $$ for the repairs, but does not want to be jacked around with someone who knows nothing about these cars!! (You know what I mean).

 

 

  Thanks, Todd

[Junkie]

Has the timing belt ever been changed? I believe that's an interference engine, and it could be that one of the cams slipped. 

[BratRod]

This one? http://dallas.craigslist.org/mdf/cto/4444317470.html

[1 Lucky Texan]

used engine (car-part.com)

 

or, you could let these guys (in Flower Mound) take a look; http://www.awdtuning.com/services/general/

[SUBARU3]

 Yes...that's the car, but he really does not want to sell it. I'm inclined to think it's headgasket. Can a head gasket blow completely on just one cylinder? The compression on the other 3 cylinders is within 2 pounds of each other. 170s

[1 Lucky Texan]

that wouldn't be a common failure mode for soobs, but not impossible I guess.

 

is it pushing coolant into the overflow or other odd problems?

 

it's more likely to be a dropped valve guide or valve problem. You could try holding a strip of paper at the tailpipe while cranking. If it tries to suck in, probably a valve problem. dropping the exhaust might let you see a dropped guide - not sure on that engine. And, a vacuum gauge might also pulse oddly if a valve were stuck/broken.

[SUBARU3]

 Does anyone know of "knowledgeable" Subaru mechanics that are reasonable in pricing in the Ft Worth area?

[1 Lucky Texan]

[SUBARU3]

  I will say that the radiator was pressurized within 30 sec from starting it COLD. Maybe that's a clue

[1 Lucky Texan]

todd, how was this determined?

and it seems to have developed, (suddenly) a zero compression cylinder.

[SUBARU3]

 Compression test, (by the guys mechanic). Reads zero

 

     I opened the radiator cap just after starting it and it sprayed everywhere.....hmm. Unusual.

 

   I want to try to help this guy somehow. He is a student and without any "Subaru" or automotive knowledge really. If I could just get a good referral for him to a decent and fair mechanic in the DFW area, that would be a start.

[1 Lucky Texan]

you could try verifying with a vacuum gauge I guess;

Here is a quick summary of Engine Testing With A Vacuum Gauge from the internet.

----------------------------------------------------

Vacuum Gauge Engine Performance Testing

A vacuum gauge shows the difference between outside atmospheric pressure and the amount of vacuum present in the intake manifold. The pistons in the engine serve as suction pumps and the amount of vacuum they create is affected by the related actions of:

 

Piston rings

Valves

Ignition system

Fuel control system

Other parts affecting the combustion process (emission devices, etc.).

 

Each has a characteristic effect on vacuum and you judge their performance by watching variations from normal. It is important to judge engine performance by the general location and action of the needle on a vacuum gauge, rather than just by a vacuum reading. Gauge readings that may be found are as follows:

 

Normal Engine Operation

At idling speed, an engine at sea level should show a steady vacuum reading between 17" and 21" HG. A quick opening and closing of the throttle should cause vacuum to drop below 5" then rebound to 21" or more.

 

General Ignition Troubles Or Sticking Valves

With the engine idling, continued fluctuation of 1 to 2 inches may indicate an ignition problem. Check the spark plugs, spark plug gap, primary ignition circuit, high tension cables, distributor cap or ignition coil. Fluctuations of 3 to 4 inches may be sticking valves.

 

Intake System Leakage, Valve Timing, Or Low Compression

Vacuum readings at idle much lower than normal can indicate leakage through intake manifold gaskets, manifold-to-carburetor gaskets, vacuum brakes or the vacuum modulator. Low readings could also be very late valve timing or worn piston rings.

 

Exhaust Back Pressure

Starting with the engine at idle, slowly increase engine speed to 3,000 RPM, engine vacuum should be equal to or higher than idle vacuum at 3,000 RPM. If vacuum decreases at higher engine RPM's, an excessive exhaust back pressure is probably present.

 

Cylinder Head Gasket Leakage

With the engine Idling, the vacuum gauge pointer will drop sharply, every time the leak occurs. The drop will be from the steady reading shown by the pointer to a reading of 10" to 12" Hg or less. If the leak Is between two cylinders, the drop will be much greater. You can determine the location of the leak by compression tests.

 

Fuel Control System Troubles

All other systems in an engine must be functioning properly before you check the fuel control system as a cause for poor engine performance. If the pointer has a slow floating motion of 4 to 5 inches - you should check the fuel control.

 

 

Performing A Vacuum Gauge Test

Connect the vacuum gauge hose as close to the intake manifold as possible and start engine. Run engine until normal operating temperature has been reached and then allow to idle.

NOTE: Vacuum readings will vary according to the altitude in different localities. From sea level to 2,000 feet elevation all normal engines should show a vacuum reading between 17 to 21 inches. Above 2,000 feet elevation the vacuum reading will be about one (1) inch lower per each 1,000 feet rise in elevation.

 

 

 

 

CHART OF VACUUM READINGS

 

Engine Speed Reading Indication of Engine Condition

Smooth and steady idle

(800 to 1200 RPM) Between 17 to 21 inches Engine is in Good Condition, but perform next test to be sure.

 

Open and close throttle quickly Jumps from 2 to about 25 inches Engine is in Good Condition.

 

Smooth and steady idle Steady, but lower than normal reading Worn rings, but perform next test to be sure.

 

Open and close throttle quickly Jumps from 0 to 22 inches Confirms worn rings.

 

Steady idle Intermittent dropping back 3 or 5

divisions and returns to normal Sticky Valves. If injection of penetrating oil into intake manifold temporarily stops pointer from dropping back, it's certain the valves are sticking.

 

Steady 3000 RPM Pointer fluctuates rapidly, faster engine

speed causes more pointer swing Weak valve springs.

 

Steady idle Fast fluctuation between 14 to 19

points Worn intake valve stem guides. Excessive pointer vibration at all speeds indicates a leaky head gasket.

 

Steady idle Constant drop Burnt valve or insufficient tappet clearance holding

valve partly open or a spark plug occasionally miss firing.

 

Steady idle Steady 8 to 14 inches Incorrect valve timing. It must also be remembered that vacuum leaks and/or poor compression can result in a low vacuum reading.

 

Steady idle Steady 14 to 16 inches Incorrect ignition timing.

 

Steady idle Drifting from 14 to 16 inches Plug gaps too close or points not synchronized..

 

Steady idle Drifting 5 to 19 inches Compression leak between cylinders.

 

Steady idle Steady below 5 inches Leaky manifold or carburetor gasket, or stuck manifold heat control valve.

 

Steady idle Floats slowly between 12 and 16 inches Carburetor out of adjustment.

 

Blipping engine speed Quick drop to zero then return to

normal reading Muffler is clear.

 

Blipping engine speed Slow drop of pointer then slow return

to normal reading Muffler is choked or blocked.

[SUBARU3]

 Good summary!  The situation boils down to the fact that I personally don't have time to help him work on this car. (I could and I do work on these cars, but it's a time issue). I need to get him to a good Subi guy that has the time and  (will be paid) to help him.