2004 Pontiac GP running on hot side

[clinebarger]

EDIT

I looked up the stock fan calibration for a '04 Grand Prix GT2, 3.8L Series III/4T65E......

One very interesting thing about your car.....It obviously has cooling stack/air flow/frontal area issues as the fans are not disabled at speed.
Vehicles that have good air flow across the exchanger's usually have the fans disabled above 40 mph, Less efficient systems disable them at higher speeds (My Camaro is set a 60 mph)

Your vehicle's disable speed is set above the limiter (maxed out)!

 

[Trav]

I suspect that could account for the GTP using a thicker core, most all the Pontiac W bodies had poor air flow to the radiator.
One thing I noticed over the years is many loose or have badly damaged chin spoiler and being primarily a bottom breather this appears to effect air flow to the radiator.

Interesting about the earlier fan relays, its similar in operation to VW's fan control module.

 

[clarkflower]

Thanks! Interesting.. All was fine yesterday and last night.... till I shut the AC off. Then got a bit hotter than normal. Then was fine when when I put it back on. I'll check fluid in a few.

Also...Pressure test scheduled Monday morning and I'll call and get a UOA kit. Who is fastest?

 

[wag123]

Originally Posted By: clarkflower
Pressure test scheduled Monday morning

You don't have to pay for a pressure test. Most auto parts stores will loan you a pressure tester and the procedure is far from rocket science.

 

[clarkflower]

Thanks...he's a friend of a friend who unlike me is a mechanic and said he will help me find the problem.
My big fear is a catastrophic type loss like anti freeze in the oil. Pretty sure I have a fluid loss that is not visible to me. I've seen oil and green fluid mixed but not the red stuff. Can you tell as easily.
I found my Blackstone Kit but not sure how fast they report back

 

[Trav]

I have used Blackstone in the past they were fast enough. I recently got some kits from Rock (or forget who it is, Wix maybe?) for $10 that I will be trying at some point.
The oil might get milk shake looking if there is enough coolant in it but more likely in small amounts it will look brown but without the translucency of untainted engine oil.

Leaks into the intake ports of the head is just as bad and may not show in a UOA or visible leak but can be very damaging causing hydro lock.

 

[clarkflower]

Thanks
I’ve seen the milkshake with the green coolant so I know what it looks like.
There is absolutely no sign of that.
I just have no idea if this red coolant looks the same...or if you can see it.

 

[clarkflower]

One follow up here.
On these cars is an intake manifold gasket something you should do preventatively.
Like if I find a radiator leak.. Should I just go ahead and do the intake manifold gaskets anyhow?
98k car

 

[Trav]

Absolutely 100% be proactive with this repair. If I buy a car with one of these engines its an automatic LIM gasket job right off the bat. I don't like checking and worrying about something I can take care of in an afternoon for a few bucks especially when it is widespread known issue and one of the very few these engines have.

 

[clarkflower]

Thanks. My big fear would be doing it and then needing a head gasket.

Way back I wasted money on a BMW 525 water pump when I had a bad head gasket. The mechanic assured me the head gasket was fine and it was until the car hydro-locked 2 weeks later. The repair quotes of 2500 were higher than the value of the car (2000 at Manheim Auction) so I sold it for 800.

Any idea what to pay for the job? Is it a job a mechanic with no shop who goes from car lot to car lot can do or should I take it to a shop; and pay a bit more?

 

[Trav]

Not on this engine, that would be rare, the 3.1/3.4 yes but not the iron block/iron head 3.8. Similar metal engines expand and contract at the same rate so there is much less HG movement trying to tear it apart (that is the reason for the black PTFE coating).
GM used a good HG on these, no worries.

 

[clarkflower]

Thanks Trav!!

 

[clarkflower]

Btw you said LIM.. Do you do the upper too

 

[clinebarger]

Originally Posted By: clarkflower
Btw you said LIM.. Do you do the upper too


You must remove the upper to access a couple of the LIM bolts.

Carefully inspect the upper plenum for being soft around the EGR outlet pipe using a sharp awl, If it's at all soft......Replace the upper plenum!

I like using a Delco replacement, Where some techs like the Dorman because they send a reduced diameter EGR outlet pipe. They miss the fact that the outlet is a close fit for a reason.....To cool the exhaust gas as it enters the intake.

 

[Trav]

Correct me I'm wrong but the egr chimney issues were on the Gen II the gen III i thought went back to aluminum. Still have to replace the upper plenum gasket though.
On the GenII I use tthe once from ATP with the reduced diameter chimney and steel egr sleeve in the plenum.

 

[clinebarger]

Originally Posted By: Trav
Correct me I'm wrong but the egr chimney issues were on the Gen II the gen III i thought went back to aluminum. Still have to replace the upper plenum gasket though.


Forgot about that....Thanks for clearing that up!!

 

[clarkflower]

Thanks again all!

Small leak from the water pump (and that's a relief knowing it was not going in the oil)
I am doing the LIM job Trav suggested as it's going to go sooner or later.

 

[Trav]

The OE pumps are tested for 112K of reliable use so if its at or beyond that point is time for some TLC on that gasket, tensioner and elbows job to take it the rest of the way, which it will with no trouble.
BTW run Mobil 1 ow40 or PU 10w30 with half a bottle of rislone zinc in that engine with the PU (the M1 ow40 already has 1100 ppm).
the tri metal bearings in that engine will thank you.

Edit: Added link. I learned this working on a lot of these engines and tearing them apart. 5.5 0z rislone zinc will bring the 800 ppm PU up to 1100-1250 ppm which is what these engines were meant to have originally.

https://www.walmart.com/ip/Rislone-3X-Concentrated-Oil-Supplement-with-Zinc-Treatment/52628126

 

[clarkflower]

Thanks. I've been running the 5-30 Mobil 1. I'll switch

 

[clarkflower]

The LIM gasket was intact but sweating. I forgot the JD Coolant and was not there. He flushed and added the regular green stuff. Any issues? Can I just drain and add it now that the green stuff is in?