Overheating Problems

[Wagon92]

Hey Guys,

Last night my car overheated in about 5 mins from starting it up after work, i had to take it over to the pits 2 weeks ago so i took it to a mechanic before it went to check over it, the guy said my radiator was leaking so he changed it ( i also changed my termostate 2 weeks before that because it was getting stuck) they also said my leads were getting old and were occasionally miss firing, so i changed them the other day, now this happened so i took it back to see what they thought it was. Got a call a apparently water is getting in through my heads in to my cylinder and Im loosing all my coolant through there. Does anyone have any thoughts on this? i would have thought is would have just been the gasket? Any help would be great. Oh and its a 3.8 ecotec in a VX Series II Wagon

Cheers

 

[Brett_jjj]

Sounds like the usual ecotec problem of leaking/blown inlet manifold gaskets. Theyre fairly cheap and easy to replace.You can get metal type replacement inlet manifold gaskets, which are supposed to last a lot longer than the standard plastic type.

 

[Wagon92]

Cheers Mate, You recon there taking the piss about getting the heads replaced?

 

[Brett_jjj]

Yeah, Id definitely be getting a second opinion. Get the engine compression tested and get the cooling system pressure tested too. Both these tests are fairly cheap to get done, and they will give you a good idea as to whats wrong. If the engine is losing compression, then there could be a problem with the heads or head gaskets etc and it will need further investigation. If the engine compression is good, then Id say its just stuffed inlet manifold gaskets, as its such a common problem with the ecotec engine once its got a few k's up, and these gaskets once blown, will cause coolant to leak into the engine.
If you do get the compression test done, get the mechanic to write down the compression pressures for you, the minimum cylinder compression figure is 689 kPa(100 psi) for the ecotec. Compare all compression readings taken, the lowest reading for any cylinder should not be less than 70% of the highest reading of any cylinder.

 

[Wagon92]

Alrighty, I'm going to get it checked tonight, and I just remembered when I changed the plugs one was wet? Not sure if it was fuel or water

 

[Dayvo]

Check to see if you have coffee colored residue under the oil filler cap .Thats one indication that the inlet manifold is leaking .

 

[som]

Providing that the mechanic hasn't been telling you porkies, I think that head gasket (s) are more likely,especially seeing as this problem began because of overheating. Coolant in a cylinder is not normally a sign of a dodgy inlet manifold gasket and overheating would not normally cause an inlet manifold gasket to blow out.Have you done a compression test yet?At the end of the day,if you're doing the job yourself,it's not that much harder to do all your top end gaskets at the same time.Imagine how dirty you'd be if you spent 4 or 5 hours,head down and arse up,only to find at the end the you've only done half a job and the problem still exists.Plus with the heads off they too can be thoroughly inspected and possibly skimmed.Your choice so good luck.

 

[Wagon92]

The cars done almost 240000 so I will probably Get reconditioned heads, as you said I don't wanna do all that and find out I still got a problem, is anyone form Perth and know anywhere thats good to get a set of heads?

 

[m1lky]

Unless your heads are cracked or badly warped. Just skim them and replace the gaskets and seals. Don't see a need for reconditioned heads.

 

[Brett_jjj]

Coolant in a cylinder is not normally a sign of a dodgy inlet manifold gasket and overheating would not normally cause an inlet manifold gasket to blow out.

Nearly every V6 commy that Ive replaced the inlet manifold gaskets on, (and ive done quite a few now), has had coolant going into the cylinders via the leaking inlet maifold gasket(s), It gets in down through the intake ports. The coolant then gets pumped out through the exhaust pipe


Before wasting money on skimming heads etc etc, check them with a straight edge and feeler gauge to see if they are even warped in the first place.. These cast iron heads are pretty robust and it takes a bit to crack or warp them, unlike alloy heads which will warp if you look at them wrong.