So I have a 00 blazer 4.3l.. I replaced the temp sensor and my temp gauge still doesn't work..
in redoing my intake gaskets should I replace the heads aswell.. I wanted to on the safe side and have need parts put in..

 

I don't think I've heard of many instances of a regularly maintained 4.3L having the head-gaskets fail. The lower intake gaskets definitely can fail catastrophically and without warning. This is why when I did my LIM gaskets I didn't bother with the cylinder head gaskets. Do you have any reason to suspect doing the head gaskets is necessary? On this point perhaps someone else will have an opinion that could help you.

Regarding the temp gauge, I've attached some scans from my 99 Service manual. It looks like the fault could be with the wiring, the sensor or the gauge. An OBD reader could be useful.

Let us know what you learn.

 

I agree with Christine. Head gasket failures are pretty rare, whereas lower intake manifold gasket failures are ubiquitous. The LIM gaskets are also MUCH less work to replace than the head gaskets, so I wouldn't bother replacing the head gaskets as preventative maintenance.

 

I'd go to Rockauto and get a mechanical sensor and gauge for $20. You could test it without installing. If it works maybe you could install it.
Alternatively, get the wiring connector for $10 and try that. if that does not solve the problem it must be the gauge, which is on the expensive side.

 

In doing the intake gaskets, I decided to replace one of the head gaskets. In hindsight, I would definitely not remove the head if it's not necessary.

The exhaust manifold was a pain in the butt to remove. The ground bolt at the rear of the head is tricky because the transmission tube is in the way. The lower rear head bolts are awkward to reach. Upon removal, there 19 extra bolt holes to be chased with a tap, 13 head bolts and 6 exhaust manifold bolts.

To top it all off, there are two extra surfaces to be cleaned, the block and the head. And these surfaces need to be squeaky clean.

Also, it is possible the head is warped. This is measured with a straight edge and a feeler gauge. The service manual specifies maximum warpage of .004 in within a 6 inch area. If the head is warped, I would be worried that it might not seal properly.

 

So I had a big Crack on the rhythm and 2 on the lh.replaced them both but now I xant seem to attach the tyranny plroperly..it moves side to side and scooting back alot.