georgi6

Hi guys,
I bought recently Impala LT 2008, 3.5L Flex. There are three leaks for fixing.

1. Transmission leak - looks to me from transmission oil coolant fittings. Bought them both form dealership.
I noticed one of them ,the longer, has some grease in it.


Should I left it there? What is the torque specification?

2.Coolant leak - system lost 150g(5oz) every 20mi. There are no visible leaks. Tested system under pressure of 15psi. It lost 2psi for a hour. Motor oil is clean. No white smoke from exhaust. No smell inside the car.
Any suggestions?

3.Oil leak - the oil pan and drain plug are in drips. It looks leak is coming from the rear side of the engine, higher from oil pan.

sledge.impy

I can't explain your loss given your test results.

Is your system properly bled?

Is this a stant pressure tester? You did lube the gasket up with coolant?

Anyways - I don't remember this being in the test procedures of an hour test... Last time I read that manual in 1999?... I've never done that. You are probably losing pressure out of the connection with the pressure tester...

If you pump that thing up and it holds - you are should be fine in my experience.. you'll know if you have a leak pretty quick... you can hear the coolant flowing and see the pressure drop.

The stant manual makes mention of running the car and examining the needle to test your head gaskets for leaks.. I remember it saying the needle should bounce around. I can't say I've seen this condition.

*umm, be careful removing if the cooling system in pressurized. very slowly let that pressurization out and protect yourself, especially if hot. The stuff boils at less than pressurized system conditions.

tech2

coolant crossover gaskets are common for coolant leaks. the leak will be seen on the passenger side of the engine.

georgi6

Could you tell me the part numbers? Any link to OEM parts catalog?

I found on Rockauto 1 left and 2 right
ACDELCO Part # 2512062 {#12623852} GM Original Equipment
Left $7.03

ACDELCO Part # 12623853 GM Original Equipment
Right; W/3 BOLT DESIGN $7.94
ACDELCO Part # 2512058 {#12577704} GM Original Equipment
Right; W/4 BOLT DESIGN $16.95

sledge.impy

gmpartsdirect.com: Alternate GM Catalog

??

georgi6

Thanks for the responses.
Per ACDelco customer service this grease must not be there. So I removed it before installation. Torque specification is 18 lb ft for both fittings. I was able only the vertical one to tighten per specs. I noticed before and after new installation there are free move back and fort on the both lines to connections. Is it normal?
Next step will be the coolant crossover gaskets. I sent an email to GM customer service about that - 2 business days no response. In my understanding it must be possible if we know at what time in 2008 they changed gasket and to determine what time was the car produced by VIN #. For now it is a mystery. I am going to by both types and will see after disassembling which one the car needs and will return the other to dealership later.

tech2

yes, the cooler hoses do move in the fittings. after pushing them into place. give them a tug to make sure they are snapped in and can't come out....then snap the black plastic secure over the clip end.

georgi6

I did this report to save time for this who wants to DIY.
Coolant crossover gaskets replacement

1. Detach hose from coolant reservoir. Drain the coolant with multifunctional pump (more than 1gal). Remove the reservoir – 2bolts x 10mm
2. Detach the cable from the clips at generator and steering pump with flat screwdriver.
3. Release drive belt from tensioner – adaptor 3/8“ to torque wrench, turn clockwise. Reposition the belt in the front area.
4. Detach battery positive cable – 10mm.
5. Generator - Detach positive terminal to generator – slide the boot, then bolt 15mm, put boot back over the connector in case you need to lock or unlock the car (battery on). Detach other terminal from connector (I broke it because was unable to release it). There are 3 bolts x15mm, 37lb ft. First is facing to you, the other 2 facing to the rear. I used offset wrench then ratchet. The further one is a stud. On it is attached a pipe from steering pump by bolt 10mm, then the hardest part – 15mm.
6. Idler pulleys – 2 , the upper – 15mm, lower -13mm; 37lbft
7. Bracket – 3x15mm, 37lbft
8. Power steering pump – 3x13mm, 18lbft. Suck the fluid (about 100ml). Detach upper end of the rubber hose. Remove three bolts. Reposition the pump.
9. Reposition radiator upper hose and the hose under it on the right side of crossover pipe. Use hook for stacked hose.
10. Remove coolant crossover pipe - 5 bolts x15mm, 37lbft. One is located at rear side, one in the middle and 3 on the left end forming triangle. Removed the both gaskets. Cleaned from residues. Installed new gaskets and attached all bolts and rotated them on 2-3 turns to keep the gasket in position.

All that job took me 6 hours. I hope having this instructions you are going to do it for 3 hours.

The assembling is in a reverse order. It took me 3 hours.
Pay attention for the cable when positioning the steering pump. The pump should be in front of cable.
If you want to flush the cooling system and replace orange antifreeze with green add 3 hours for every day. I drained it from the petcock on radiator (left lower corner of radiator when facing it) – the more you wait the more you drain- I waited 2-3 hours. Then pour the fluid and burp the system. Put about one gallon distilled water. Turn ones the radiator cap. Run the engine, raise the revolutions to 2500 for 40sec, shut off engine, remove the cap, and burp the system squeezing the top big radiator hose, then top off: repeat for 30 sec at 2500 rev, than 20 sec. Tighten the cap and do 3x 4sec at 3000 and 4sec at idle. This is by manual. I replaced the second part with running the engine at 1800-2000rev, start the heater to feel when is hot air – thermostat is open, wait a minute and shut off the car. Next 3 days check and add fluid as needed when system is cold.

At the end I would like to share my disappointment from the service manual ($220). There was no information for the location of the bolts, nothing about their size. No how – for instance: generator – remove 3 bolts… No pictures – sketches only, like the book was issued in the 70s. To use YouTube is better than that book - the problem is there are not sufficient information. I am sure if we share our experience here we can make our live easier.

tech2

and gm warranty pays the tech 1.8hrs. how would you like to get paid 1.8 for your 6 hours of work? That's why no tech likes doing warranty work.

georgi6

I replaced these gaskets but it looks the coolant leak still exist. I read an article how to diagnose for blown head gasket. Part 1 -GM 3.5L Index of Articles
I did first 2 tests - OK. I would like to do now the Compression Test to Check for a Blown Head Gasket. The question is how to remove the rear spark plugs? I can't see them at all. The engine is 3.5L V6