Chev Blazer 1998 Oil

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hi guys,

my dad just gave me his old blazer 98 and he told me that he has been using 20w-50 oil for a long time, but the truck has had some over heating issues, and the heater core wasn't longer working, the a/c is not working either. (i don't know if it has any relation with the oil)

well, the manual says that according to my weather (41 to 77 F) i should use 15w-40 and it's time to do the filter and oil change.

what would you recommend me, stay with the 20w-50 that has been using for a long time (more than 50.000 miles) or change it to 15w-40?

thanks a lot!

pd: it usually runs at 40 psi and around 200 F.
 
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I'd go with any major brand 5w-30 or 10w-30 that's availible to you. No need to be any thicker then that. If its burning oil (hence the thicker oil) a replacement PCV valve is an inexpensive and relatively easy and probable fix.

For the heater core, bypass it by disconnecting the two heater hoses under the hood and couple them together with a coupler and hose clamps, should be all available at a local auto parts store.
Then flush, refill, and bleed the cooling system, then take the overheating diagnosis from there.
 
First thing I'd look at is the fan clutch. Any oil should do. I assume this has the 4.3 liter V6?
 
A Chevy Blazer in Italia? Mamma Mia! You can use almost anything in that engine, it's tough. 5w-30, 10w-30, 15w-40.
Whatever you do don't use Colavita, put that in your salad.
 
That is amazing that the Blazer calls for such a heavy oil in Italy. In the USA, most GM trucks called for 5w30 year round, 10w30 when 5w30 isn't available, and suggest using 0w30 synthetic in extreme cold.

As for the cooling system, there is probably better advice in the coolant section and in the repair section.

Some people have suggested that using a cooling system cleaner with citric acid is a good idea, and you can get that citric acid based cleaner from a Mercedes Benz dealership.
 
Originally Posted By: eljefino
First thing I'd look at is the fan clutch.


Yup. It is easy to diagnose and simple to change.
 
20W-50 is so European.
I don't think that this grade was ever recommended for any US or Japanese brand in the US.
It used to be among the commonly recommended grades for a variety of Euro cars including my old BMW.
A 5W-30 would have been recommended for this engine in the US, so I'd look for something a little thinner than a 20W-50, depending upon what you can get locally for reasonable money.
A 10W-30 would be perfect and a 10W-40 would be better than a 15W-40 or a 20W-50.
I would think that it might be rather expensive to slake the thirst of one of these anywhere in the EU.
Welcome to the forum and enjoy this new to you old ride.
It must be a pretty rare machine in Italy.
 
Originally Posted By: NTech

my dad just gave me his old blazer 98 and he told me that he has been using 20w-50 oil for a long time, but the truck has had some over heating issues, and the heater core wasn't longer working, the a/c is not working either. (i don't know if it has any relation with the oil)


The first thing to look at: Remove the radiator cap and see if it looks like someone secretly replaced your antifreeze with something that appears to be red dirt. Hopefully it won't be like that.
 
The heater core Door Acuator is a common problem in those. They fail once in a while & cause the heater to not work. (I had to replace mine last year in our 1996 Chevy/GMC)

The part you want is: Heater Blend Door Actuator

They are a cheap and require some removal of the glove box and screws under the dash. Takes about 20 minute to fix it yourself.


AS for the oil, stick with 5w30 or 10w30. The 20w he used is way too think for that motor and year.


GL
 
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