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Just clean and replace the manifold gaskets.
Does not take too long to do it.
One note for you, the small vacuum hose at the back of the manifold, add about 3 or 4 inch extension to it. From the factory they are just long enough to connect.
So it appears my Oil Pressure Sensor has now failed me on my ‘01 after 90,000 miles.
From what I have read on here I have three options:
1- Have my wife and her tiny little hands reach way in the back, try not to break or drop anything, and hope for the best.
2- Cut a big fat hole in the windshield cowl, and replace from the top.
3- Remove the Intake Manifold and replace it like a boss.
since my wife has big hands that won’t happen, and ain’t no way I am cutting a hole, so that just leaves pulling the Intake off.
Since the manifold is off, beside clean and replace new gasket is there anything else I should do to take advantage of it being off?
Replace additional sensors, upgrade any hoses, replace Intake or fuel lines?
not looking forward to this so want to make the most of a bad situation better
thanks in advance!
🍻
Removing the intake is really not too difficult. 10 bolts total, 5 on each side. Some guys use clothes pins to hold the bolts up, so the manifold can be pulled forward. I just pull the bolts up as needed. You're lucky you got 90,000 miles out of the OEM unit. Personally, I'll never buy another GM oil sender for my C5. But that's just me. Most use a torque wrench to bolt the manifold back down. I don't remember the torque specs. I want to say 189inch/lbs (15.75foot/lbs), but do a search and make sure you have the correct torque specs. Good luck......
Removing the intake is really not too difficult. 10 bolts total, 5 on each side. Some guys use clothes pins to hold the bolts up, so the manifold can be pulled forward. I just pull the bolts up as needed. You're lucky you got 90,000 miles out of the OEM unit. Personally, I'll never buy another GM oil sender for my C5. But that's just me. Most use a torque wrench to bolt the manifold back down. I don't remember the torque specs. I want to say 189inch/lbs (15.75foot/lbs), but do a search and make sure you have the correct torque specs. Good luck......
Curious, want the best, what would be the preferred Oil pressure sensor?
The MAP sensor is the only other sensor back there but it is attached to the intake manifold and you shouldn't need to worry about replacing it unless you're having issues with it.
I would also highly recommend doing a relocation of your new sensor. The oem units had brass bodies that were more rugged but all of the new replacements are aluminum and seem to be prone to quick failure. I just replaced mine this past summer and the replacement (Standard Motor PS308) failed 10 miles later.
I built a relocation kit with a brass Buick sensor with the following pieces and it's been good since. When/if this one fails, it will be a 2 min replacement without any disassembly of other parts.
As stated above, take the intake off to change it, definitely do the relocate - it makes it sooooo much easier to do it in the future, replace your gaskets, blue (242 or 243) Loctite on your intake bolts when you re-install.
Torque sequence below - tighten in 2 passes. 44in-lbs on the first pass, 89in-lbs on the second. On bolts 8 and 9, I use a zip tie to hold them about an inch above where they sit when they are unscrewed, this will help when you remove and reinstall the manifold.
One thing to be careful about are the vacuum connections at the back of the intake, AND the MAP sensor In particular the little plastic vacuum line goes to the vacuum accumulator. That little line may be brittle and can crack. The brake booster line is fairly big, and the connection barb can break. 20YO plastic that has seen a lot of heat......
Unless a mod has been done, you have a coolant vent line under the throttle body to remove and some coolant leakage when you remove.
Once you loosen the intake move it forward easily so you can see what is going on WRT these connections.
You will need a 3/8 release tool for the fuel line. Relieve fuel pressure before releasing the stainless braided hose. Be very careful with the locks on the purge valve and the ribbed “snake hose” that connects to the fuel vapor canister vent line to the purge valve. The gray plastic lock on the purge valve pushes in slightly to release, and unless you work on these connections frequently, you are tempted to take a pick and remove the lock. Bad idea to use a pick. The push point is not obvious, so be patient.
Also a good time to clean the throttle body and MAF. and replace the gasket to the intake. Be very careful when cleaning the MAF. The sensor wires can be broken.
Agreed on the vacuum lines and would add the gasket between the coolant cross over and heads to the parts list. Yes many odds and ends but the newest C5 is 17 years old. If it hasn't been touched and you're moving stuff around do it all at once IMO.
I never disconnect the fuel line. I lay it over on a protective mat at the base of the windshield.
I have had the intake manifold off twice so far. The second time I found it was a little easier to remove the throttle body first, which makes it easier to move the manifold forward enough to have room to disconnect the big brake booster vacuum line and other connections at the rear of the manifold. I agree that if you remove the manifold, relocate the sender unit to make it easier to change in the future. My car is on its third sender. It is also a good time to bypass the throttle body coolant heating line.
Note- disconnect the fuel line to the manifold, but the injectors and fuel rails stay on the manifold after removal.
Yes, extend the tiny vacuum line at the rear to make it more certain it is re connected when you reinstall the manifold.
Removing the manifold is the only way to get the area underneath and adjacent to the intake ports clean. I recommend you tape up the intake ports before cleaning. A small nut or piece of something hard falling down an intake port and through an open intake valve will likely require removing that head. Do not forget to remove the tape.
I recommend new intake manifold gaskets.
If you relocate the sender,you should also consider adding a mechanical pressure gauge at the new location. That way when the newest sender fails again, you can open the hood and verify that the engine still has oil pressure.
I did not do anything with the knock sensors, but if you do, FSM knock sensor torque is important. Some have reported problems after replacing knock sensors and have had to remove the manifold again to rectify, possibly because of over torqueing the sensors.
Your 2001 has the rear head coolant air bleed ports blocked off. Earlier C5 cars had the rear coolant air bleed ports connected via piping under the intake manifold to the front head coolant air bleed ports. If you track the car, research this issue. There are some assertions that the lack of coolant air bleed from the rear heads has contributed to rear cylinder failures in 2001 and later cars on track. Probably anecdotal, but I did connect the rear coolant air bleed ports on my car the last time I had the Intake manifold off. Because of the design of 2001 and later C5 intake manifolds, it is easier to run rear head coolant air bleed piping and hose out from behind the intake manifold and over the top of the passenger side head instead of under the manifold as was done on earlier cars.
Working room behind the manifold is very tight with the manifold in place.
My guess- GM decided that the rear coolant air bleed ports were unnecessary, so they were blocked off. Maybe old wives tales are involved regarding rear head coolant air bleed discontinuance/ rear cylinder failures. But I connected mine.
The secondary air check valve for the passenger side secondary air injection system is behind the intake manifold. If (when) it fails, the intake manifold will again have to be removed for access. There are a few posts on the forum on how to relocate or abandon that valve in place, the new location to be adjacent to the passenger side head with an air line to the secondary air injection system on the driver side, around the front of the engine.
i cut the hole. you'll never know it's there and should have been done at the factory. it's a 10 minute job after that and you'll probably have to replace one in the near future anyway. there are several places where you can install a remote for this problem. have seen the video's that use extensions without removing the manifold and would love to see those guys replace mine that way. if you don't mine removing the intake go for it. reminds me of the fuel pump removal on my 92 s-10. did it once then installed a trap door there in case it happened again.
thats your right. be sure to remove the wipers and cowl cover to make sure it has no hole cut in it when inspection your c5's. or any small hole in firewall for gauge wires and such. there are lots of things we do to our c5's to make them the way we want them. if you don't want to cut holes thats ok.
i cut the hole. you'll never know it's there and should have been done at the factory. it's a 10 minute job after that and you'll probably have to replace one in the near future anyway. there are several places where you can install a remote for this problem. have seen the video's that use extensions without removing the manifold and would love to see those guys replace mine that way. if you don't mine removing the intake go for it. reminds me of the fuel pump removal on my 92 s-10. did it once then installed a trap door there in case it happened again.
Itried to put an extension on mine, and could not find any way to tighten it. Can't use a socket and a crows foot doesn't work.
Bad Oil Pressure Sensor -Options?
You can also build your own kit
