RTV on L98 intake install?
Thread Starter
LS/MFT
Joined: Jun 2000
Posts: 5,874
Likes: 0
From: Cary IL
St. Jude Donor '09-'10-'11-'12
RTV on L98 intake install?
Need to R&R the intake on my '90 L98 to repair the all-too-common front and rear oil leaks. Do I put RTV on the intake gaskets around the coolant passages? Does the new gasket (Felpro) seal the coolant passages without RTV? When I put the RTV on the front and rear of the engine valley, do I let it skin over first, or install the intake with the RTV wet?
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
First roughen and dimple the mating area along the front & rear engine lands and under the intake base; then wipe down with brake parts cleaner.
I put a thin layer of RTV around each water passage, laid the gasket in place and then put a thin layer on the top side of the gasket. I immediately laid down two thick beads of RTV on the front & rear engine lands, trailing up onto the gaskets a little.
Then I laid the intake base straight down onto the lands with NO forward/aft motion and installed the Torx bolts (which had some Permatex #2 on the threads). Once the bolts were torqued in sequence & steps to the proper spec I let the job stand over 24hrs. Then I retorqued the bolts and installed the rest of the pieces.
To answer your question, do NOT let the RTV skin over, install the base immediately over the wet RTV. The point is that the RTV must adhere well to both surfaces for a long lasting bond and seal.
I put a thin layer of RTV around each water passage, laid the gasket in place and then put a thin layer on the top side of the gasket. I immediately laid down two thick beads of RTV on the front & rear engine lands, trailing up onto the gaskets a little.
Then I laid the intake base straight down onto the lands with NO forward/aft motion and installed the Torx bolts (which had some Permatex #2 on the threads). Once the bolts were torqued in sequence & steps to the proper spec I let the job stand over 24hrs. Then I retorqued the bolts and installed the rest of the pieces.
To answer your question, do NOT let the RTV skin over, install the base immediately over the wet RTV. The point is that the RTV must adhere well to both surfaces for a long lasting bond and seal.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
Instead of RVT silicone, use Permatex "THE RIGHT STUFF". Better than normal silicone. Do a search on the forum and you will find many suggestions about your installation. Highly recommend that you dimple the block and intake manifold with a center punch between the heads. 
This gives the sealant something to grasp. You will not regret doing this. 
I have used this on several cars and trucks, works great! Be sure to clean all other surfaces with lacquer thinner or brake cleaner. They MUST be oil free for a good seal. GOOD LUCK!!
This gives the sealant something to grasp. You will not regret doing this. I have used this on several cars and trucks, works great! Be sure to clean all other surfaces with lacquer thinner or brake cleaner. They MUST be oil free for a good seal. GOOD LUCK!!
Pro
Joined: Feb 2005
Posts: 658
Likes: 1
From: Centerville OH
Originally Posted by 65Z01
First roughen and dimple the mating area along the front & rear engine lands and under the intake base; then wipe down with brake parts cleaner.
I put a thin layer of RTV around each water passage, laid the gasket in place and then put a thin layer on the top side of the gasket. I immediately laid down two thick beads of RTV on the front & rear engine lands, trailing up onto the gaskets a little.
Then I laid the intake base straight down onto the lands with NO forward/aft motion and installed the Torx bolts (which had some Permatex #2 on the threads). Once the bolts were torqued in sequence & steps to the proper spec I let the job stand over 24hrs. Then I retorqued the bolts and installed the rest of the pieces.
To answer your question, do NOT let the RTV skin over, install the base immediately over the wet RTV. The point is that the RTV must adhere well to both surfaces for a long lasting bond and seal.
I put a thin layer of RTV around each water passage, laid the gasket in place and then put a thin layer on the top side of the gasket. I immediately laid down two thick beads of RTV on the front & rear engine lands, trailing up onto the gaskets a little.
Then I laid the intake base straight down onto the lands with NO forward/aft motion and installed the Torx bolts (which had some Permatex #2 on the threads). Once the bolts were torqued in sequence & steps to the proper spec I let the job stand over 24hrs. Then I retorqued the bolts and installed the rest of the pieces.
To answer your question, do NOT let the RTV skin over, install the base immediately over the wet RTV. The point is that the RTV must adhere well to both surfaces for a long lasting bond and seal.
