: How good is the 4.6L N*



Roswell256
03-01-04, 09:06 AM
I've got a '94 DeVille Concous. It has a 4.6L N* and I was wondering how good these engines are? I've been reading up on the forum here for a while and have found that the 4.9L is considered one of the best engines made. But what about the 4.6L? I haven't found too much on them here. that means that they either run so well that noone has a problem with it or there are so many problems that everyone has gotten rid of them. Let me know what you think

Thanks,
-Roswell-

BeelzeBob
03-01-04, 10:02 PM
I've got a '94 DeVille Concous. It has a 4.6L N* and I was wondering how good these engines are? I've been reading up on the forum here for a while and have found that the 4.9L is considered one of the best engines made. But what about the 4.6L? I haven't found too much on them here. that means that they either run so well that noone has a problem with it or there are so many problems that everyone has gotten rid of them. Let me know what you think

Thanks,
-Roswell-

There is a lot about Northstars on this forum...this whole section is devoted to Northstars, right? You can read about all the "problems" here...just remember that there are a couple of million Northstars running around and only a few people bothering to look up this forum to vent and look for help.

Overall, I think you will find that the Northstar engine is very robust and very reliable. There are some chronic complaints about oil consumption that is partially explained by the fact that the engine is a high performance engine and is designed to use a little more oil than older design engines, partly by people overfilling and using synthetic oil that tends to exacerbate oil consumption in the engine and partially because some of the engines are babied to death and the rings stick in the pistons due to carbon build up. The Northstar was designed to be run hard and it likes frequent bursts of WOT to keep the carbon out and excercise the rings and make sure they are seated and mobile.

The earlier engines 93/94/95 were factory filled with the conventional green coolant that needed replacement every 2-3 years/24-32 K miles to keep the corrosion inhibitor strength correct. If it is allowed to become depleted then internal corrosion can cause damage including head gasket problems. The engine is relatively easy to repair....it just requires the proper techniques, tools and procedures as outlined in the factory manual. Most people that relate poor repair experience did not use the correct procedures or tried to apply some old school engineering to the engine...sure course of failure.

Roswell256
03-03-04, 10:25 AM
You said that it comes prefilled with the regular green coolant. I know for a fact because of water pump troubles and t-stat replacement that its been filled witht he "Dexcool?" , is that right?. Well its the red stuff. My question is does that need to be replaced as often, less often, more often, then the green stuff?

BeelzeBob
03-03-04, 11:52 AM
You said that it comes prefilled with the regular green coolant. I know for a fact because of water pump troubles and t-stat replacement that its been filled witht he "Dexcool?" , is that right?. Well its the red stuff. My question is does that need to be replaced as often, less often, more often, then the green stuff?

Well...I know for a fact that the factory originally filled it with the conventional green silicated coolant....that is a positive known fact. The DexCool was first installed at the GM factories for the 1996 model year. It was an "across the board" change for GM and it happened for 1996 model cars and engines....

So...your 94 originally had the green silicated coolant. Someone converted it to the DexCool at some point in time. This is good and bad. Good in that you at least know that the coolant was changed at some point before you got the car !!! The bad is that once the engine was run with the original silicated green coolant the cooling system is "plated" with silicates which cannot be purged or removed. The presence of the silicates tends to negate the long life effect of the DexCool coolant....so....you still need to change the coolant every 2-3 years/24-32K miles...whichever comes first. It is no big deal....you just still need to change it to keep the corrosion protection up to full strength. Since there is no long life advantage to using the DexCool in a pre-96 model there is really no reason for retrofitting the system with DexCool...but...since yours is already converted I would continue to use it...just drain and refill every 2-3 years/24-32 K miles to replenish the corrosion inhibitor package in the coolant.

Lawrence
03-03-04, 08:15 PM
bbobynski,

My 94 STS which as you know has a new service engine installed 03/97 was converted at that time to Dexcool. Was this a GM policy? If so they would have had to replace the radiator?

BeelzeBob
03-05-04, 12:28 PM
bbobynski,

My 94 STS which as you know has a new service engine installed 03/97 was converted at that time to Dexcool. Was this a GM policy? If so they would have had to replace the radiator?

I don't think that it was any sort of policy at all to change the cooling system over to DexCool. Since it was a new engine it was fine, though, as the hot part of the system (the engine) is the main place the silicates were deposited and since that was replaced it was OK to convert to DexCool. That was the dealer that did the work's decision, though, not a GM policy. The rad is compatible in any case. I would still change it frequently, though , as there are likely some silicates still contaminating the system that would tend to slightly neutralize the corrosion inhibitors long life....