How to check an engine's condition

lodhi12 (lodhi12) 2008-10-19 11:58:00 +0600 #21

@displacement_on_demand

When i say loss of compression on any 1 piston, I DO NOT mean a difference of many bars.
e.g 3 pistons shoe compression of 120, 1 shows upto 110.
It doesnt mean anything. Usually the seating of the piston becomes dry and occurs in CNG cars.
When car runs on petrol, it produces lots of CO2, so that gets deposited around the piston and in the chamber, keeps the pressure normal. This doesn't happen in CNG cars bceause almost no CO2 is made.

lodhi12 (lodhi12) 2008-10-19 12:00:00 +0600 #22

I am not an expert, so if i am wrong, please do correct me.
But this info is correct as far as my knowledge goes.

CAR9 (CAR9) 2008-10-20 03:10:00 +0600 #23

@ displacement_on_demand : then what u suggest about the position of engine

iceman_kimi (iceman_kimi) 2008-10-20 05:33:00 +0600 #24

@Naweed,

Thanks a lot for the help. I'll act on your advice (clean area and check mileage). I don't get similar driving conditions everyday so mileage may or may not be a good indicator. Actually I travel on Islamabad highway, and you might know that it is under construction. So one day I get a clean road and on another day I have to bear stop n go traffic.

Plugs were cleaned 3 weeks ago on my last tuning. Oil level seems fine (hasn't reduced enough for me to notice even though I have been to chakwal and back through the motorway (i.e. @100-120kmph).

Thanks for the info regarding the excitation wire. As far as I understand the lead from HT to distributor gives out more pulses than the 1st lead, doesn't it? What role does this wire play?

I'll definitely go to either of the CNG mechanics mentioned (most probably 2). Can you please instruct me about getting the compression. Where and cost?

iceman_kimi (iceman_kimi) 2008-10-20 05:35:00 +0600 #25

@displacement_on_demand
I was just trying to help. Never claimed to be giving out smarter ways of doing things, just passing on knowledge that I have accumulated over the time. Your clarification and direction is much appreciated.

racerali (Ali Siddiqui) 2013-09-12 06:52:14 +0500 #26

iceman_kimi;1317404:

Good question. I've heard of several ways which include the following:

1: Checking if gray smoke comes out of your car in the morning right after the cold start. If it does than that means the engine is week.

2: While the engine is running open the engine cap (the round one). Invert it and check if its inside is oily. You could also place your hand on the hole left by this cap (if the engine cover is not too hot) and rev the car a bit. If you get oil on your palms that means the engine is weak.

3: Water drops coming out of the silencer also represent a good engine. (I'm not too sure about this one though).

4: Good pick also indicates a strong engine. If your car is tuned and yet if it doesn't accelerate as you press the pedal that means you have a weak engine.

These are some of the techniques I've seen mechanics apply these to check engine condition.

Experts opinion sought thought.

Saad bhai i m little disagree with you
on 2nd point that if engine cap is oily it means engine is weak i have 3 cars 1 honda civic 2010,honda civic 2000,suzuki bolan 2013
all of them have oily engine cap when removed

ahmedk06 (ahmedk06) 2013-09-12 07:28:46 +0500 #27

a bad PCV valve and a good oil pump also show oil deposit on oil cap, that is not the right way to check an engine. The best easy way to check an engine is a compression test. All other indicators can be faulty. Compression guage for petrol engines can be found in market for something around 2500-3000/-
Cold exhaust at cylincer is also a good indicator,

afnan.bashir (afnan.bashir) 2013-09-12 14:49:06 +0500 #28

Well there are many tips but most important is that you must not have huge tons of work instantly. If you are buying a used car obviously you would have some issues with engine if its old.
When i do I check as following.

Open the Oil cap while car is started. If there is loud Blow with Smoke its a bad......... Some cars have throw but importantly you should see for Smoke.
Pull out the Oil Dip Stick and see if you see bubbles and white creamy color this means there is water mixing with engine oil
Hear for any extra Vibration or noises, rattling noises etc.
If its EFI check if its correctly cutting of at specified RPM
Check the drive if car feels under power and slow throttle response there may be fuel pump or regulator dying out
If its Automatic Check if it kicks down? and check for shifting jerks
Check for Oil Leaks near Head and below Engine where ever its possible. Also notice the leakage duration if it was a leak and its old then it would be dry and dusty
Check for Engine Vibration in Drive and Neutral for Excessive Vibration....... Your mounts may be weak or dead
Check Exhaust for any black Smoke deposit if yes car us having problem with fuel mixture may be bad o2

racerali (Ali Siddiqui) 2013-09-12 15:36:05 +0500 #29

afnan.bashir;4045535:

Well there are many tips but most important is that you must not have huge tons of work instantly. If you are buying a used car obviously you would have some issues with engine if its old.
When i do I check as following.

1. Open the Oil cap while car is started. If there is loud Blow with Smoke its a bad......... Some cars have throw but importantly you should see for Smoke.

2. Pull out the Oil Dip Stick and see if you see bubbles and white creamy color this means there is water mixing with engine oil

3. Hear for any extra Vibration or noises, rattling noises etc.

4. If its EFI check if its correctly cutting of at specified RPM

5. Check the drive if car feels under power and slow throttle response there may be fuel pump or regulator dying out

6. If its Automatic Check if it kicks down? and check for shifting jerks

7. Check for Oil Leaks near Head and below Engine where ever its possible. Also notice the leakage duration if it was a leak and its old then it would be dry and dusty

8. Check for Engine Vibration in Drive and Neutral for Excessive Vibration....... Your mounts may be weak or dead

9. Check Exhaust for any black Smoke deposit if yes car us having problem with fuel mixture may be bad o2

Sir

i have an engine when Open the Oil cap while car is started there is loud Blow without any smoke

2nd when Pull out the Oil Dip Stick there is bubbles but not creamy color and the coolant is not reducing

the engine oil is not a drop less when change
this car is honda civic 2000 with JDM engine
has good pick and mileage
can u plz tell whats wrong with it

afnan.bashir (afnan.bashir) 2013-09-12 15:47:08 +0500 #30

For honda engines and some others Blow with sound is not a problem until there is smoke out of it. Color is critical if its not creamy as like coffee you are in luck........ it has nothing wrong. I have accord and it has loud blow............... but no smoke its fine

racerali (Ali Siddiqui) 2013-09-12 16:42:59 +0500 #31

Thanks for the reply sir
Its engine oil color cannot change as i use caltex caltex havoline formula 10w30 and the original color of that oil is same when change
because of i change at 2500km to 3000km

afnan.bashir (afnan.bashir) 2013-09-12 16:58:38 +0500 #32

its not the brand, when water mix inside engine the color does change..........

racerali (Ali Siddiqui) 2013-09-12 18:31:28 +0500 #33

No no sir you take my words wrong. As I m describing you that engine is in good condition that engine oil color not change to black .so why it gives bubbles to dip stick

Sent from my GT-S6102 using PW Forums mobile app

PKTUN (PKTUN) 2013-09-13 04:10:44 +0500 #34

bubbles or foam may be lubricating detergent in synthetic oils that cause foam / bubbles zulfiqar rustam ser_gtr are right people to answer such queries

afnan.bashir (afnan.bashir) 2013-09-13 11:09:40 +0500 #35

You may have checked after running the car. If the oil level was at the appropriate level and its not coffee color, don't give it a second thought.

Xulfiqar (Xulfiqar) 2013-09-13 11:10:58 +0500 #36

all oils will change color due to oxidation, soot and scrubbing the engine.