2002 S40 1.9T - Crank/No Start Condition

JoV · Post by **JoV** » 04 Jul 2012, 03:43

2002 Volvo S40 1.9 DOHC Turbo, 115k mi. Vehicle was bought with a crank / no start condition. Previous owner states vehicle overheated and has sat since. On visual inspection, no obvious evidence of leaks or faulty hoses. System was refilled, still no obvious leaks. There is spark at all 4 cylinders, fuel pressure is 40-45 psi at the rail with KOEO. Dry compression test, in order is 135/130/120/130. There is evidence of some coolant pooling on top of piston #4. Codes present were P0236/P0237/P0107. Both MAP sensors where removed and cleaned and only code left is P0107.

Some strange things I noticed was that if holding pedal down during crank, car would sometimes start. Also extreme pressure at coolant reservoir tank when cap off after start attempts. The fan seems to start right away even though vehicle never started or even got up to a temp. First Volvo I ever worked on or owned, so any help is appreciated. Thank you in advance.

Post by **jimmy57** » 04 Jul 2012, 08:49

The engine got hot and destroyed coolant sensor so the ECM runs fan as default.
Pressure in the cooling system is NOT good when it develops when cranking.
Are the plastic covers for spark plugs and the back timing belt cover melted?

The likelihood of engine being serviceable when the back timing belt cover melts as well as getting hot enough to "fry" the ECT sensor.
P0107 can be set for the MAP sensor, which sticks into the intake manifold back by runner for #4 cylinder, got hot enough to also be "fried".

You can pull cylinder head and inspect. The steel cylinder liners having the aluminum backed away from them is a no-go.
The slot cut between cylinders should be the same distance wide across. If it closes down from heat, also a no-go.
The top face of block not being flat is a no-go.
Then there is cylinder head. Forget the .20mm across/.50mm lengthwise Volvo specs. Look for between bolt holes, especially on exhaust side and the "dam" between cylinders, to be no more than .12 mm in that span.
If it runs really hot the exhaust side between bolt holes (this area is below the exhaust ports where no coolant to control temps would let this area get VERY hot and warp readily) will get over .20mm and even over .30 mm.
The head can be cut almost .30mm but it will need to be oven straightened first so the cam bearing surface/top face of head is flat.

Is the car is great shape otherwise?

JoV · Post by **JoV** » 04 Jul 2012, 12:57

Hey jimmy thank you for the quick reply. Yeah, otherwise the car is in excellent, excellent condition, worth saving. Yes you are correct, the thin plastic engjne covers were a little melted. So what do you suggest is the best approach? Pull the head, get it checked and machined? How would you approach this problem to get it running? Thanks again in advance, your help is greatly appreciated!

Post by **jimmy57** » 04 Jul 2012, 13:08

Pull the head and inspect. If the block has the conditions listed there is no need to do anything to that engine.

JoV · Post by **JoV** » 04 Jul 2012, 13:16

Okay, so if the block has those signs it is toast and un-repairable? So engine swap is called for if so? Just wanted to clarify, I am going to start to disassemble and inspect today. Will take some pics and post for your thoughts if that's alright. Thanks again.

Post by **jimmy57** » 04 Jul 2012, 13:25

From experience if the gap between cylinders is closed and the aluminu has separated from the steel cylinder liner then the rings may have heated to the point of sticking rings in ring lands on pistons or they have lost the tension to seal on cylinder wall. The risk of block deck warpage is high in that case too.
Do you know why it over heated?

JoV · Post by **JoV** » 04 Jul 2012, 13:37

Looks like just from neglect, lack of coolant. No visible damage, leaks or evidence of stoppage anywhere. OK, will tear into it and update.