2004 Blazer 4.3 liter tapping when cold.......

[labs4ever]

You can buy the pressure tester at any automotive parts store. It sounds as though that you have probably lost a head gasket, probably around the number 3 cylinder. Usually the intake gasket will leak at the upper part of the intake ports of the number 1 and 2 cylinders. I have done a few of these in the last couple years. I took preventative measures when I bought my truck. I knew of the Dex-Cool issue so I immediately flushed my entire system and went with a coolant usually used in RV generators. Its a yellowish green made by Prestone. I have had it in my truck since 2003 and no issues.

[dab1123]

To all with cold temp. tapping issues & all concerned with proper care of vehicles:
While I am not permitted to advertise on this site/blog, I would like to assist everyone with lubrication, filtration tips & vehicle longevity.
Contact me:
Web site: http://www.lubedealer.com/worldsfinestsynthetics
Email: [email protected]
[email protected]

[bandit7862]

Originally Posted by labs4ever

My 2000 blazer had tappet noise from day one. About 3 years later I threw caution to the wind and I used the old trick we used in our tractors for loud engines. I replaced one quart of engine oil with 1 quart of Marvel Mystery Oil. Aftera few days the noise has stopped and now I use it every oil change. However, I change my oil every 2000-2500 but just because I work my blazer alot harder than it should be.

labs4ever,
does that marvel mystery oil really work or is it just another money making name? My 4.3 liter engine only taps loudly when it is cold, but a few days after the oil change, it is quiet as a bug. My Blazer works hard too and usually running it about 75 to 100 miles a day. If you think that mystery oil will work, hell, i'll try anything to get this embarassing lifter ticking to stop. Thanks for the tips.

[labs4ever]

Well, I cannot guarantee anything being a consumer, all I can tell you is the results we have had using it. My father ran mystery in is 1984 suburban, the body is all but gone, engine has just under 400k on it. Our 96 Suburban has 270K on it, my 90 Sierra has 230K on it, the Blazer that I work like a mule has 214K on it. The only vehicle here that hasn't some kind of extreme duty is the 96 Suburban, it only tows a small sailboat, everything else is farm related. The Blazer is my personal workhorse, it tows hay wagons, gravity bins, plows snow and it urges a few cattle now and again with the front bumper/cattle guard to go in the right direction. Another person I know who swears by Marvel is a friend of mine who uses Marvel in the fuel and oil of his Cessna 310 twin engine airplane. Not only does it clean and lubricate the valves, injectors, it also has reduced the wear found on the internals during the required engine overhaul times. I hope I have given you reason to try it at least. Oh, and we use it in our 1926 Farmall tractor also.

[oneav8or]

Sorry it took so long to get back to you bandit...been working for the last day changing the intake manifold gasket. Went pretty much as advertised, just took a while to get everything off so I could remove the manifold, and then a quick inspection showed...(drum roll please) the gaskets where in bad shape, broken in several places and obvious signs of collant leaking and one in particular, leaking into the top of the engine down into the cam (was the drivers side rear of the manifold). Took me around 7 hours maybe, with all the cleaning I did. That guide blazes posted was pretty much right on, except the newer blazers there is no way to move the electrical harnes bundle out of the way, and you need help to hold the bundle up so you can get the manifold back in. I did not remove the fan, but I did remove the alternator as it was easier to get to the heater hoses and something else (can't remember what).

As of today it's not leaking, and no tapping on start up....although with new oil, it didn't do it anyway......but there is a tick coming from the bottom of the engine....hope it is not the main bearing damaged and getting ready to go.

Bandit, the pressure tester came from Autozone, one of those rent/borrow tool loaner things. It's self explanitory really, goes on where your rad cap is and has a bicycle type pump you pump up to pressure and look for leaks. I had one on the drivers side that I could see just barely trickling out on the front when pressurized...but never saw it there when the engine was just running at idle. That leak never made it too the ground while sitting at idle, but I guess the pressure wasn't high enough until probably highway speeds and it just spewed all over the bottom of the engine and wisked away by the relative wind. Yours sounds the same as mine though, and most likely is the intake manifold gasket leaking. DONT MIX THE TWO ANTI-FREEZES as you will end up with a brown sludge in your system that will gum up everything. Really it wasn't bad, and the hardest part I think was loosening the power steering bracket as the nuts (two on the lower part in the back) are kinda hard to get to I think. Have one other person help you, I had two volunteers actually that thought it would be good to see how it's done. If you are in the St. Louis area I would be glad to help out. I'm not an expert by any means, but I guess the water from the coolant is getting evaporated by the heat of the engine? The oil I drained did not seem to have any water in it, although it's heavier and would have sank to the bottom, but it was black, def not what I expected after only a few hundred miles, and it was thinner than it should have been for the miles since last oil change. I spent around 86.00 $ for the gasket, 2 gallons of prestone dex-cool (not premixed) and 2 gallons of distilled water, 5 quarts of oil and a filter. Had 3 quarts of oil on had already to pour though the upper part of the engine to "wash" all the crap down to the oil pan. Had to flush the heater core as I guess all the junk I didn't get, clogged up the heater core and my heat wasn't working. Sorry for the long post.

Originally Posted by bandit7862

oneav8or,

Where did you get the pressure tester from and how exactly do you hook it up? If this is the best way to check for a leaking intake manifold gasket, I want to try it before doing this huge job. Also, before I am able to attack this job, I have been changing my oil about once a month just to keep it running and it has been keeping my lifters fairly quiet temporarily. My lifters start ticking again when cold about 3 weeks to a month after the last oil change. Lastly, It was getting expensive to keep pouring dexcool into the radiator and reservoir, so I heard I could use the green anti-freeze instead of the orange dexcool. I was losing about a quart of coolant every week or two with no visible signs on the ground or around the engine. That is why I was asking if I could be losing this coolant out the exhaust manifold because I cannot find a leak. Maybe it is leaking out the exhaust while driving. Is this possible? I now have heard that you should never mix the 2 colors of anti-freeze. I am not sure which is correct. Any suggestions would be great to know.