Engine Vacuum

[sandman577]

Patulong sana ako sa mga meron alam sa makina.
Im planning to buy a 2nd hand car.
Sabi kase sa akin before buksan ko daw lagi yung oil cap, tapos dapat daw pahigop (vacuum sya) , dapat wala daw natatapon na oil pag binuksan mo.

Tama ba to? Meron kase ako natry before na 2nd hand car. Tapos nong binuksan ko yung oil cap, palabas yung buga ng hangin at tumatalsik yung oil. Ano sira ng makina pag ganon? Pasira na ba pag ganon? Advisable pa ba sya na bilhin or hindi na? Need na ba na ioverhaul yung makina pag ganon yung condition?

Hingi lang sana ako ng advise nyo. Additional tips na din with regards pano tumingin ng makina ng car.

thanks in advance

[niky]

That means piston ring blow-by, and is a sign that you will probably have to rebuild the engine. It's air escaping past the piston rings and into the oil galleries, causing pressure build-up under the oil cap.

Unless you're getting the car for almost nothing, or getting a 50k to 100k discount for the blown engine, stay away.

Typically, you should check the radiator and coolant bottle for signs of oil contamination (the fluid will look milky) or rust or scale build-up (signs that the previous owner didn't use coolant... which means you will have to replace the radiator and/or water pump in the near future.

You'll also want to see how the car behaves in traffic, whether the electronics or ignition coils start acting weird when they get hot (if you are allowed to test drive, that is). Check for "kalampag", shock problems and sticky brakes while you're at it. Those aren't deal-breakers like the other problems, but you should ask for a discount if it has any of these issues.

[duskylim]

Dear sandman577:

The only conclusive test as to whether the engine has lost compression (called 'blow-by') is to use a compression gauge.

The pressure read should be the recommended pressure plus or minus 10%.

Anything over this and the engine needs to be overhauled.

Regards,

Dusky Lim

[sandman577]

niky and dusky lim thanks sa advise.

For duskylim:

Baguhan lang kase pagdating sa engines. Can you provide me the recommended pressure pra sa 1.6L na sedan. 2001 Gli corolla to be exact.

Regarding sa compression gauge, special gauge ba yan or tipong pwede ko lang bilhin lang sa auto shop and easy to use? or klangan ko dalhin yung car sa isang shop pra itest with the compression gauge.

How about sa tunog ng makina. Is there an indication na sa tunog pa lang ay meron ka na kahit idea man lang na hnde na ito good conditon.

Please advise

Thanks

[duskylim]

Dear Sandman577:

Sorry but I don't have the compression specs for a 2000 Corolla Gli. These are listed in the factory or the service manual. A competent repair shop o yung casa should know these specs.

Since you are thinking of buying the car an not opening a repair shop there is no reason for you to get a compression gauge. Also good quality gauges are expensive.

It is best for you to rely on a good repair shop for the test. Pero bihira pumayag ang mga nagbebenta. So good luck there.

What niky said still applies, if it blows bluish-white smoke out the exhaust or you can see oil smoke coming out of the engine's breather, then what has happened is that the oil rings or valve oil seals may be suspect.

The best thing to do is to have a trustworthy competent mechanic accompany you to test the car you have chosen BEFORE you BUY.

Best Regards, and GOOD Luck!

dusky lim

[niky]

Compression for a naturally aspirated 1.6 will usually be around 150-200 psi... the exact number will vary from engine to engine, but the important thing is the cylinder-to-cylinder number... as long as the cylinder compressions are within 10-20 psi of each other, the engine is okay.

As for sounds... a noticeably loud ticking or pinging or backfiring (on a stock car... modified exhausts sometimes cause backfiring on otherwise good engines) are sounds you should look for.