I have a 2000 Stratus with 185,000 miles. It’s been a great car. I did the timing belt, water pump just over a year ago. Recently, the car engine stopped while my daughter was driving on the interstate. She said no warning; car just lost power.

The car cranks but won’t start. I did a compression test with throttle floored. Here are the readings 40 20 20 50 – car cold. I put a squirt of oil in the cylinders and the numbers are 70 50 50 85.
(Increased 30psi almost equally on each cylinder).

I discovered that the coolant level was very low so I thought the car had overheated. I have a compressor so I pressured up each cylinder to 125psi. And listened for leaks on each cylinder I did not hear anything and the pressure did not drop. I also used a fresh battery.

I just can’t figure out why the pressure is so low across all the cylinders. Thanks for your input.

 

have you checked the timing belt ,if it jumped it could cause low readings and show minimal leakage .the increase when you added oil sounds like worn rings or cylinders

 

Make sure and replace the idler pulley and tensioner pulley along with water pump and t-belt this time....if you decide to get it fixed again.

Don't rely on or use the compression test for a diagnosis until you know for sure that it IS in time. If the belt did come off, put a new belt on THEN run the compression test. FYI, when the belt comes off, it will have an unmistakeable sound when it cranks over....nice and "smooth".

 

I pulled the top timing belt cover off, and the timing belt is in place. The engine didn't sound right when I was cranking it - too smooth I thought/or not enough kick from the battery. So I re-did the comp. test with a better battery. Got the same results.

I didn't replace the "idler pulley and tensioner pulley" when I did the timing belt last year. And I just have a hard time accepting that the timing belt slipped a tooth or two. There's no slack in that timing belt. However I agree, that I (First) need to make sure that the engine is timed correctly. So I'll pull the crank pulley an have a look.

The replacement car I bought needed a "Head Gasket". So after I finished that project I incorrectly jumped to that same thought pattern with this car.

Thanks for the guidance. I don't know what else could cause this. I've never seen results like this when I've done a compression test.

 

Were the cams turning when you cranked it over with the upper cover off?

When an engine is out of time, depending on the manner it's out of time (one cam off, both cams off, the crank just spinning in place over stripped belt teeth, inline or V-type) Compression will/may vary on different banks or uneven between companion cylinder pairs. It all depends on the layout. In some cases it can even have high compression. For example, when the exhaust valve, rocker or lobe is inoperative OR the exhaust valve opens very late.

In the case of your inline 4, the companion cylinders are 1/4 and 2/3. Companion meaning that the pistons are in the same position at all times but on different strokes (compression/exhaust are both going upward, intake/power going downward)

 

I pulled the crank damper pulley. The timing belt is in perfect condition and all the timing marks line up correctly (according to Haynes repair Manuel). "That fix would have been too easy".

I asked my daughter about the details of when the car died. This is what I discovered.

1. Car started to over-heat a week earlier. She noticed the gauge reading. She pulled over
and the temp. dropped quickly. So she then drove on with no more problems (gauge stayed normal. Coolant level was low so she added coolant.

2. The night the engine died. She started to lose power. 50 - 40 -30 -20mph until the car died. No noise - no smell. She did notice small amount of white smoke from the engine area after the car stopped.

I noticed that the coolant level was extremely low when I started to look at the car. My guess is the engine overheated.

Any idea what I should do next. I'm guessing a leak down test. I have no problem pulling the head off, but looking for suggestions before I do that?

 

Update:

I did a leak down test starting with #1 cylinder. Results were 80 percent loss. I didn't hear any air leaking - tail pipe, throttle, oil fill tube.

I then decided to hook the connector directly to the air compressor. The leak down tester wasn't feeding much air into the system. (Note: I incorrectly said I pressured up the cylinders in my first post - I was incorrect - I pressured up the Compression testing hose. I forgot about the Schrader Valve, on the end, not letting the air into the cylinder).

When I pressured up the cylinder, I started pushing coolant out of the system. I could also hear the air leaking into the next cylinder. I pressured up two more cylinders, a had the same results.

So the head gasket is blown across all the cylinders (What the chance of that happening) or the head is cracked? No coolant in the oil. So time to take the head off and see how things look.