[red_rider52]

Hello I have a 1990 Chev pickup with a 305, I am loosing antifreeze and there are no leaks and I think it is going into the oil. The oil is not milky but is almost like tar. I did a comp test and all the cylinders are between 145 and 150 psi except for one that is at 160, what would cause this? a blown head gasket?

Thanks for any help.

[1931 steve]

The compression is nothing to worry about its not that far off from cylinder to cylinder. The coolant loss could be many things. The head gaskets are a known problem on these engines and so are the intakes. Poss cracked engine block but I would suspect the head gaskets or the intake gasket first. How much coolant are you loosing?

Steve

[red_rider52]

I'm not exactly sure how much I am loosing it has been a couple of months that I have driven it, but it is a noticeable amount I had to check it often and ad every couple of days. The truck also overheated before when the fan belt broke.

[red_rider52]

I also forgot that one plug was a little bit darker in color and that one was the one with the higher psi. Also once I get the intake off is there any way of telling if its intake gasket that blew? so I do not have to take the heads off? or should I just to both?

Thanks again for any help

[1931 steve]

The track record of that engine, says do the head gaskets also. How many miles do you have on the engine? If its a high millage engine, I would suggest sending the heads out to a machine shop and have the checked and serviced.

Steve

[56Maynard]

See any coming out of the weep hole on the pump?

[red_rider52]

There is about 150,000 miles on the truck and a lot of them is towing 4,000 or 5,000 pounds around. I was going to bring the heads in to get them serviced if I took them off.

I am sorry but I don't know what the weep hole on the pump is could you explain thanks.

[1931 steve]

[QUOTE=red_rider52 I am sorry but I don't know what the weep hole on the pump is could you explain thanks.[/QUOTE]

If you look at a water pump face to face you will see a small hole in the case at aprox 6 o'clock. This hole is called the weep hole because most of the time they will weep coolant from it.

With that many miles I would suggest a head inspection and a head job.

Steve

[1931 steve]

Sorry more explication, The weep hole is under the shaft that comes out where the pulley bolts to the pump, on the housing.

Steve

[Oldphart]

I don't understand your comment that the "oil is not milky but is almost like tar". With that said, on a high miler truck like this I would try a can or even two of radiator stop leak, change the oil, and then watch it closely. I've successfully used this stuff on leaking freeze plugs etc with no apparent negative effect.

[red_rider52]

I always thought when you get water in your oil it will turn a milky color, but the oil that came out of the truck was like sludge or tar very thick, I did an oil change on it then changed it after about 1000 miles and it was thick like that again.


I also got thinking and was wondering if it was a head gasket that the coolant would go into the cylinder and be burnt off and not go into the oil. and if it was the intake gasket it would go directly into the oil.

let me know what you think.

[1931 steve]

Originally Posted by red_rider52

I also got thinking and was wondering if it was a head gasket that the coolant would go into the cylinder and be burnt off and not go into the oil. and if it was the intake gasket it would go directly into the oil.

let me know what you think.

It could go either way, with the head gaskets. Sounds like the oil has not been changed often enough.

Steve

[red_rider52]

I would change the oil and filter about every 3000 miles

[Oldphart]

Just my opinion but I'd still try radiator stop leak unless you have bigger plans for the truck that include an engine tear down. On that subject I recently read what I thought was good advice from Docvette on a similar problem.

See below.

Just prior to pulling the engine down, get a can of K&W block seal, follow the directions (to the letter) and run a can through it.

The object here IS NOT to seal it up , or a snake oil fix, but K&W has suspended copper in it...when you go to pull the engine down, you will notice GOLD STAINS everywhere it had a leak.