A friend has a coolant leak on his Blazer. Not the best picture ever, but where it's circled... there is coolant bubbling right there (when it's running). It appears to be just below the valve cover coming from the intake manifold? He's really hoping it's not a head gasket. Could it be possible that a head gasket leak could manifest right there? Also, the oil is good and clean. No sign of coolant contamination. Thanks!
2002 Blazer 4.3 Coolant Leak
- Thread starter Blang
- Start date
4.3's rarely ever blow headgaskets, however they do commonly blow lower intake gaskets.
This to me looks like a lower intake gasket leak just like what happened on my 4.3. I replaced mine using a Fel-Pro upgraded gasket kit, be sure you use the upgraded style which is metal reinforced whether it be Fel-Pro, Mahle, or Victor Reinz.
Also do not forget high temp thread sealant otherwise you could have some oil wicking up the bolts eventually, and this would be a great time to replace the distributor which is another common failure point if you have not already done so.
This to me looks like a lower intake gasket leak just like what happened on my 4.3. I replaced mine using a Fel-Pro upgraded gasket kit, be sure you use the upgraded style which is metal reinforced whether it be Fel-Pro, Mahle, or Victor Reinz.
Also do not forget high temp thread sealant otherwise you could have some oil wicking up the bolts eventually, and this would be a great time to replace the distributor which is another common failure point if you have not already done so.
Lower intake gaskets for sure. The OE gaskets are plastic, and if they're original then they're well past their service life. It's not that tough of a job: always use the upgraded metal gaskets when doing the job.
Also, I HIGHLY recommend replacing the OE fuel injector "spider" with the updated unit from GM. Part # 19210688, costs $240 from RA. After 20 years, the old plastic fuel injectors will be well past their service life.
Also, I HIGHLY recommend replacing the OE fuel injector "spider" with the updated unit from GM. Part # 19210688, costs $240 from RA. After 20 years, the old plastic fuel injectors will be well past their service life.
Being that his is a 2002 he likely already has the 4.3 LU3 (which he can verify by looking for LU3 on the firewall or on RPO codes in the glove box) if so those come with the updated injectors. 2002 was the year the LU3 was launched.
I had a feeling that there was a running change in there somewhere, I just couldn't recall for sure. It's becoming more and more rare that I service early Vortec engines.
Awesome. Thank you. That makes me feel a lot better. I'll make sure he gets the quality gaskets.
Thank you! I told him I wanted to look at the injectors. I replaced spiders on an 01 several years ago.
Sweet. I confirmed that it's a 2002. I'll double-check the RPO. Thanks!
Update... it appears to be an 4.3 L35... Looks like it still has the spiders. I helped him tear into it a little this evening. Called it a night early since he's gotta get up early for work. It looks as though the mount for the AC Compressor might get in the way a bit. If so, is that too much trouble to get out of the way?
The AC Compressor has to be removed and set to the side, you can still leave the AC hoses attached though, if it is an L35 you would probably want to consider upgrading the injectors.
'96 & up Vortec heads have blind intake bolt holes
The left bracket & power steering pump will need to be slid forward. There are 2 Nuts that need to be removed from underneath, Then the long bracket bolts & another nut.....The bracket can now be slid forward on the long stud.
I agree. I told him about the injectors.
Thanks! Does the PS pulley need to be removed? Use high temp thread sealant on the bolts for the lower intake manifold, then?
Hard to tell the location by the photo, but LIM gaskets are definitely the culprit. It is quite the job. Took me 2-3 days (evenings) to do mine. The distributor has to come out as well as basically everything on top of the engine. My gaskets looked like a dead squid.
The PS system has a large aluminum bracket with a male torx and setting bolt that needed removed too IIRC.
I’d get new bolts. They come with a thread locker. Take the old bolts and cut the head off of them. Thread them in 2-3 turns on top of the engine for “locating dowels.”
The PS system has a large aluminum bracket with a male torx and setting bolt that needed removed too IIRC.
I’d get new bolts. They come with a thread locker. Take the old bolts and cut the head off of them. Thread them in 2-3 turns on top of the engine for “locating dowels.”
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