2001 Suburban 5.3l pinging & oil usage

[BlazerLT]

Guys, honestly, look past oil and fuel being the cause.

The AC Delco Rad caps are defective in design and don't hold the 15psi they are supposed to hold.

This lowers the boiling point of the coolant and in my case was causing the engine to run 20-30f above where it was supposed to run.

Since replacing it the pinging has vanished.

 

[Steve S]

Knock sensor been checked?

 

[drm7]

BlazerLT: what brand cap should I get as a replacement? Where are these caps sold? The engine temp gauge always reads around 205 if I remember right. Is this the right temp?

Thanks!

 

[BlazerLT]

Honestly, that could be your problem, the stat should open and run around the 195 degree area most of the time unless if it is incredibly hot out.

You can buy a Stant at Autozone and they are usually 16psi which is completely normal.

Have you heard any water sloshing noises coming from the area around where the passengers foot rest area is?

 

[BlazerLT]

quote:

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Originally posted by Vortec_4300:

quote:

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Originally posted by BlazerLT:
Guys, honestly, look past oil and fuel being the cause.

The AC Delco Rad caps are defective in design and don't hold the 15psi they are supposed to hold.

This lowers the boiling point of the coolant and in my case was causing the engine to run 20-30f above where it was supposed to run.

Since replacing it the pinging has vanished.

---

Blazer -

I have a new 2005 Silverado with the 4.3l V6 as well. Can you tell me where the radiator cap is located? I removed the plastic cover from the front of the engine compartment, but the top of the radiator doesn't seem to have any cap that I can see. Is the cap you are referring to the one located on the overflow bottle?

Also, I've seeen numerous warnings not to introduce air into the cooling system. Won't removing and replacing a radiator cap allow air into the system?

I realize that these might be some dumb questions, so I apologize in advance if this seems too simple to waste any time over. I just want to do the right thing by my engine, and it sounds as if I need to replace that radiator cap immediately, before I have any issues with the coolant.

---

Your newer system might have the pressure cap on the resevoir itself.

On some GM trucks, the RAD cap is on the rad. The stock cap's fibrous rubber gasket will begin to harden and won't seal well allowing the cooling system to not maintain its 15psi pressure and also will draw in air through the cap when cooling and contracting rather than draw in coolant from the recovery resevoir.

This introduces air into the system which will degrade Dexcool incredibly fast.

Another sign that your cap is bad is if you hear a sloshing noise from your heater core near the passenger footwell area. You will hear the gurgling which is actually the air being trapped in the heater core itself.

Also, this causes a lot of heater core failures seeing the air trapped will make the coolant corosive and will rot the copper tubing causing the heater core to leak all over the passenger floor.

And no, the air introduced during the rad cap replacement is completely harmless. The closed cooling system will easily blow the excess air out the rad cap and into the resevoir when driving and the displaced air will be replaced by coolant again when you park the vehicle and the rad contracts again and draws in coolant.

 

[drm7]

Thanks BlazerLT! I'll try the rad cap by the weekend. Unfortunately I've already filled up with 93 oct which has cured the ping. It usually takes 3 weeks or so to run out the tank so by then I'll probably have a new rad cap and run sea foam through the intake. So much for scientific controls to see which one cures the problem, assuming I get it cured.

 

[Vortec_4300]

quote:

---

Originally posted by BlazerLT:
Guys, honestly, look past oil and fuel being the cause.

The AC Delco Rad caps are defective in design and don't hold the 15psi they are supposed to hold.

This lowers the boiling point of the coolant and in my case was causing the engine to run 20-30f above where it was supposed to run.

Since replacing it the pinging has vanished.

---

Blazer -

I have a new 2005 Silverado with the 4.3l V6 as well. Can you tell me where the radiator cap is located? I removed the plastic cover from the front of the engine compartment, but the top of the radiator doesn't seem to have any cap that I can see. Is the cap you are referring to the one located on the overflow bottle?

Also, I've seeen numerous warnings not to introduce air into the cooling system. Won't removing and replacing a radiator cap allow air into the system?

I realize that these might be some dumb questions, so I apologize in advance if this seems too simple to waste any time over. I just want to do the right thing by my engine, and it sounds as if I need to replace that radiator cap immediately, before I have any issues with the coolant.

 

[BlazerLT]

quote:

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Originally posted by drm7:
Thanks BlazerLT! I'll try the rad cap by the weekend. Unfortunately I've already filled up with 93 oct which has cured the ping. It usually takes 3 weeks or so to run out the tank so by then I'll probably have a new rad cap and run sea foam through the intake. So much for scientific controls to see which one cures the problem, assuming I get it cured.

---

That truck is made for 87 octane. Using expensive fuel will not cure it at all.

 

[drm7]

The manual does spec 87 and that's all I run but I put a tank of 93 in to see if the pinging would go away. The 93 stopped the pinging. I never run an octane rating above what the manual calls for. Waste of money IMO. Besides, who can afford to run expensive 93 in a Suburban?

 

[drm7]

I don't think it's the fuel either. I'm betting on carbon or maybe the engine temp as you suggested. I'll let you know if/when I solve the problem.

 

[BlazerLT]

don't be so sure, I think you have an ever so slight overheating problem causing the pinging.

I had the same thing with mine and changed practically everything.

Turns out it was the cooling system all along.

 

[BlazerLT]

Very true, but I don't think the cause is the fuel.

 

[Rhymingmechanic]

Drm7--Any news?

In reference to the radiator cap issue, I have seen info about traditional radiator caps leaking and causing Dexcool sludge in S10/Blazer engines. The new body style full size trucks have the pressure cap on the coolant reservior. My pinger has always run about one notch below 210.

Steve S asked about checking knock sensors. Will a bad knock sensor be picked up by a computer scan, or is there some other way to test? The independent shop I took mine to said they found no error codes in the computer and no mechanical problems that would cause ping. Experiences with the Chevy shops make me doubt that they even hooked up a code reader before announcing that spark knock/ping is normal.

Here's the kicker--knock sensors on the 4.3 and the last generation small blocks are easy to see and replace. The new V-8 has two knock sensors UNDER the intake manifold.

 

[drm7]

Sorry for the late reply. I injured my leg and was out of commission last week. I'm also in the middle of moving to a new house so I've been away from the computer for a week.

I swapped the radiator cap this morning. I bought a Stant 15psi cap. The temp gauge read the exact same temp as before on my commute. By my calculation it looks like it's running around 200. I thought 205 but it seems like each mark is about 6 degrees and I'm running just over 1 1/2 marks under 210.

Next I'm going to try Deep Creep (Sea Foam) to de-carbon. Then I'll try plugs. If all fails I guess I'll be forced to run the expensive gas even though the manual specs 87.

 

[Mike_dup1]

I know you all don't think this is true but I know several GM techs and they all tell they see this all the time. Its common but most drivers dont' even know its happening. Can't hear it or ignore it.

Depending on what part of the coutry you are in, it may be worse or better due to the diffenent EPA mandated fuel formulations.

You are wasting time and money trying to solve this, its fuel related. I put a brand new engine in my 1992 work truck and it pinged from the start. They tried everything and nothing will stop it. As long as I don't make it labor, it will not make much noise. My 1999 K2500 Suburban survey crew truck pinged for 4 yrs and over 100,000 miles. When the lease was up, the engine was in great shape.

Go ahead, tell me I don't know what I am talking about. My first new car was a 1966 Impala SS 396 and I can recall this engine pinged like crazy whenever I put Clark gas in it. I have been driving since 1963..

 

[BlazerLT]

Cat convertor could be partially clogged as well.

 

[dave1251]

drm7 try putting in chevron techron if you can obtain it in virgina.

 

[BlazerLT]

Just as an update, I am having problems with increasing pinging with my blazer, sloshing in the heater core and I found the solution.

For one, the rad cap had to be replaced AGAIN and the system needed to be purged to get rid of the air lock.

What I decided to do was drive the resevoir and rad cap side of the truck up onto a curb so that side was higher and elevated more than the whole engine and heater core.

I then carefully removed the rad cap and had the truck set for an idle of around 2000 rpms and wow, I watched the rad level just plummet from full to 3/4 when the thermostat opened. I then kept on adding coolant to top it up until no more air spaces were displaced.

You had to be really patient as you could see the new coolant was displacing some air in the heater core and block. I kept on doing this for about 30 mintes and seeing the rad level was no longer burping, I installed the new rad cap and I topped off the coolant overflow bottle.

Results......

Pinging is gone. Heater core no longer gurgles and engine seems to a lot more peppier.

The pinging must have been making the knock sensors retard the timing quite a bit.