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The ongoing struggle to repair my '93 Lumina Euro 3.4 head gasket includes adding a block heater to the engine. Since the rear head is removed from the block, this was the perfect opportunity to pop a block heater into place in the rear core hole. HOW COULD I GO WRONG? The process resulted in the discovery that Kat's (Five Star Manufacturing) block heater catalog lists the WRONG block heater for the VIN X LQ1 3.4 DOHC engine.
This incorrect listing is carried over to the Amazon "Does It Fit" selection guide. I bought my block heater from Amazon. As of today, 7 March 2012, Amazon still lists the Kat's 11425 block heater as fitting the 3.4 DOHC engine. I will return the incorrect heater to Amazon, which (hopefully) will result in them correcting their listing. I am also sent e-mail to Kat's; again the end result is to have them correct their catalog.
The Kat's 11425 does NOT fit. No how, no way. Not possible. At least, not in the rear (right bank) core hole as used by GM for the OEM heater (which, by the way, is no longer available from GM.) The Kat's heater element will interfere with the middle cylinder before the housing will seal to the core hole.
Kat's may make a block heater that does fit this engine. I have NOT investigated which part number is correct, but if I had the inclination I'd start with #11415. This part number was suggested to me by the local CarQuest parts expert--but they did not have one in stock to compare.
The Zerostart 3100015 pops right in. There is an obvious difference in the shape of the heater element; suffice to say that it does not interfere with the middle cylinder.
Note that both heaters are photographed without the O-ring seal; I had just finished trial-assembling them into the engine--I wanted to see that they fit, and I didn't want seal friction to add to the installation force. There is NO WAY the Kat's heater could be shoved in that hole!
Before actually installing a block heater, it's a good idea to verify that the thing is electrically sound. Plug the cord into the heater, and perform two resistance tests with a quality multimeter.
Resistance from one flat blade of the cord plug to the other flat blade: A block heater is nearly always "around" 35 ohms. Other kinds of engine heaters may have more--or, more often, LESS resistance.
From either flat blade to the round ground lug should be an open circuit--no continuity.
Resistance testing through the cord would be the FIRST thing I'd do if I suspected the heater didn't work. Usually the cord is defective, sometimes it's the heater. Easy to tell with an ohmmeter by testing the conductors separately.
The original core plug was a complete nightmare to remove, because unlike so many engines where the plug is driven into the water jacket, and then turned and pried back out using a water pump pliers as a "hook", the core plug of the 3.4 will not push far enough into the water jacket due to the middle cylinder being in the way. DO NOT drive the core plug farther into the engine! Drill a small hole off-center of the plug, thread in a sturdy sheet-metal or wood screw, and PULL the plug out using some kind of pry bar. There's no working room; you can't see it from the bottom even with the exhaust removed. If I didn't have the cylinder head removed, this would have been impossible.
Because I tried to push it into the block--and there isn't room--removing this core plug took about five hours. In the process, I scarred the core plug hole. Engine heater was installed with High Tack sealer on the O-ring for added insurance against leaks. I'm not proud of this; but please learn from my mistake!
Specified torque on the retainer bolt for the Zerostart heater is 20--25 INCH pounds. This is the same as TWO foot-pounds. I used a 1/4 inch drive torque wrench; I swear tightening by hand would over-torque the fastener.
The head gasket that started this repair disaster:
The lifter tick bulletin that became part of the head gasket repair:
Pulling '91--'95 DOHC lifters apart:
This incorrect listing is carried over to the Amazon "Does It Fit" selection guide. I bought my block heater from Amazon. As of today, 7 March 2012, Amazon still lists the Kat's 11425 block heater as fitting the 3.4 DOHC engine. I will return the incorrect heater to Amazon, which (hopefully) will result in them correcting their listing. I am also sent e-mail to Kat's; again the end result is to have them correct their catalog.
The Kat's 11425 does NOT fit. No how, no way. Not possible. At least, not in the rear (right bank) core hole as used by GM for the OEM heater (which, by the way, is no longer available from GM.) The Kat's heater element will interfere with the middle cylinder before the housing will seal to the core hole.
Kat's may make a block heater that does fit this engine. I have NOT investigated which part number is correct, but if I had the inclination I'd start with #11415. This part number was suggested to me by the local CarQuest parts expert--but they did not have one in stock to compare.
The Zerostart 3100015 pops right in. There is an obvious difference in the shape of the heater element; suffice to say that it does not interfere with the middle cylinder.
Note that both heaters are photographed without the O-ring seal; I had just finished trial-assembling them into the engine--I wanted to see that they fit, and I didn't want seal friction to add to the installation force. There is NO WAY the Kat's heater could be shoved in that hole!
Before actually installing a block heater, it's a good idea to verify that the thing is electrically sound. Plug the cord into the heater, and perform two resistance tests with a quality multimeter.
Resistance from one flat blade of the cord plug to the other flat blade: A block heater is nearly always "around" 35 ohms. Other kinds of engine heaters may have more--or, more often, LESS resistance.
From either flat blade to the round ground lug should be an open circuit--no continuity.
Resistance testing through the cord would be the FIRST thing I'd do if I suspected the heater didn't work. Usually the cord is defective, sometimes it's the heater. Easy to tell with an ohmmeter by testing the conductors separately.
The original core plug was a complete nightmare to remove, because unlike so many engines where the plug is driven into the water jacket, and then turned and pried back out using a water pump pliers as a "hook", the core plug of the 3.4 will not push far enough into the water jacket due to the middle cylinder being in the way. DO NOT drive the core plug farther into the engine! Drill a small hole off-center of the plug, thread in a sturdy sheet-metal or wood screw, and PULL the plug out using some kind of pry bar. There's no working room; you can't see it from the bottom even with the exhaust removed. If I didn't have the cylinder head removed, this would have been impossible.
Because I tried to push it into the block--and there isn't room--removing this core plug took about five hours. In the process, I scarred the core plug hole. Engine heater was installed with High Tack sealer on the O-ring for added insurance against leaks. I'm not proud of this; but please learn from my mistake!
Specified torque on the retainer bolt for the Zerostart heater is 20--25 INCH pounds. This is the same as TWO foot-pounds. I used a 1/4 inch drive torque wrench; I swear tightening by hand would over-torque the fastener.
The head gasket that started this repair disaster:
The lifter tick bulletin that became part of the head gasket repair:
Pulling '91--'95 DOHC lifters apart:
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