- This topic has 35 replies, 5 voices, and was last updated 10 years, 1 month ago by
.
-
Topic
-
Here are the symptoms:
Car 1: 2000 Grand Am. Its a 2.4 litre twin cam 4 cylinder.
Has a back fire issue.
Scanned. Code reads as follows PO171 (system too lean Bank 1) and also PO300 (Random/Multiple Cylinder Misfire Detected) Replaced the fuel filtre, all 4 spark plugs, and the coil pack. Not sure where else to start looking at solving this issue as its my sons car.Car 2: 2000 Grand Am. Its a 3.4 litre V-6
I need to keep adding coolant to this car. Doesn’t seem to be a leak or a leak that I can see anyway. My oil looks normal (not milky). Replaced the coolant reservoir and cap, top coolant hose, thermostat, water pump. Had it pressure tested about a month ago thinking maybe the head gasket and it came back normal so mechanic said.Not sure where a person should start to look for these problems. Any help would be greatly appreciated.
-
Replies
-
I can only offer some quick advice about the 3.4. That engine is known for intake gasket leaks. I’d visually inspect the intake at the ends of the heads. Most often, you’ll see the leaks on the rear bank at either end of the head. If you’ve still got your dexcool in their, the orange leak trail will be pretty obvious.
So when you say intake gasket. Is that the upper gasket. Should i be running dexcool in it as I have been running prestone in it.
So i had the V6 out today. Car runs good but have a problem with the heat in the car. When i start the car and let it run for 5 or 10 min the heater is still blowing cold air. Once the car is completely warmed up it blows nice and hot heat. Not sure what I can do here if there is still an air bubble in the cooling system or what but I have been trying to bleed system for days now and still the same results.
Can you guys recomend something?
Ah, the GM quad 4… has to be the tightest engine ever made by GM… 🙂
The ignition coil housing is notorious for failing on these. Sometimes there will be no external evidence like carbon tracking, etc., What can be more confusing, sometimes they will allow spark to get through, even when bad. I don’t think there is any way to test these. Your best price may be Amazon.com or Ebay if you need to get one.Regarding car #2, +1 on no_common_sense’s suggestion of the lower intake manifold. Sometimes these will leak slowly externally, or both externally and internally, with some going inside the engine. I’ve seen them begin to fail and for a while show no sign of coolant in the oil. Pop the pcv valve out of the front valve cover and examine it for any milky residue. Do the same with the oil cap. You can even run you finger on the top underside (inside) of the front valve cover to check for milky oil. Lastly, get a good flash light and examine where the intake manifold meets the heads (not the upper aluminum plenum above the fuel rail). This area is a little hard to see. The power steering unit makes it hard to see on the passenger side and the exhaust manifold on the driver side. Anyways, look for the presence of coolant in these areas. Try this for starts…Hope this helps…keep us posted.
With the 3.4 –
Are you SURE there are no radiator leaks? Really get in there and inspect things. Joy of joys – on at least the 90’s GM cars – the radiator would develop a leak in the front along the plastic. Usually on the driver’s side and it is kind of hard to see.
I am not saying to rush out and buy a new radiator but just REALLY inspect, get under the car and look for dried antifreeze trails, etc. Do this after it has had a good run on the highway and you fee pressure on the upper radiator hose. For whatever reason, just sitting at idle never builds needed pressure to open tiny leaks.With the quad 4 – I won’t even speculate that. I hear those engines are a REAL nightmare to deal with.
I have replaced the coil pack already. Went out to an autowreckers and picked on up for this car. What I have done recently was replace the air flow sensor to see if that has anything to do with it. Thinking to much air means computer needs to add fuel and thats possibly why the car smells like its running rich. Seems to be running ok right now but will give a few days to see if the symptoms come back.
So with the radiator. was gonna look at the radiator as said earlier in this post.(Have a parts car here so to replace radiator is no issue) Was looking at my hoses and seen that the top radiator hose attached to the radiator is attached with a hose clap (not sure if its letting air in the system) not the usual clamp used as the rest of the clamps. would you run dex cool or just regular antifreeze.
Gonna go out to princess auto and buy a coolant pressure test kit to see if I can find the leak. How long should the system hold the 15 psi.
[quote=”Hutch74″ post=116800]So when you say intake gasket. Is that the upper gasket. Should i be running dexcool in it as I have been running prestone in it.[/quote]
I mean the lower intake gaskets where they mount to the heads. No need to run dexcool. As I understand it, dexcool was the problem that caused so many intake gasket failures.
There are two coils inside the plastic ignition coil housing. I’ve replaced the 2 coils with brand new ones on the quad 4 and still had the same symptoms and codes you described in original post because of the bad housing. I’m a pick and pull fan myself, but personally never use coils and most electronic parts from them. It would be worth it to disassemble the coil housing and inspect it for carbon tracking/ discoloration. As stated previously, I’ve seen them fail and show no external signs. One final note, the quad 4’s are bad about burning up the catalytic converter when an extended misfire occurrs without going addressed. That is an expensive fix. Best of luck sorting it out.
Just visit the forums for GM owners who had that dex-cool as original equipment and ask how much they like it. Especially those running the 3800 series II.
WHEN you convert to normal green coolant, make sure to really flush the orange out. Orange and gree are not compatible and could end up sludging up.
This article describes the reason for this 3.4 L pattern failure. The original gaskets are plastic. The updated ones are metal.
http://troubleshootmyvehicle.com/gm/3.1L-3.4L/coolant-leaking-from-intake-gaskets
So I am confused. Is there 2 intake gaskets? Intake gasket is this a big job or can i do it myself? If i pressure test the cooling system will it show the intake gasket leaking (not holding constent 15psi). Is there a video in replacing the intake gsasket?
Sorry for the dumb questions but i am not a mechanic just trying to save some money as this grand am has 300k on it as its my POS car back and forth to work.
Thanks
No, the plenum gasket is mistakenly referred to as the upper intake manifold gasket. The intake manifold gasket is underneath the intake manifold itself. It is a bit challenging if one has limited mechanical experience. Here is 1 of 3 videos that will show you what all is involved. This is a common problem on the 3.1 and 3.4 engines of this vintage. Keep us posted.
- You must be logged in to reply to this topic.