Thread: Td5 cam cover sealant

Someone asked me earlier in the week what sealant to use for the corners of the "d" on the td5 cam cover gasket. I've been using a permatex RTV but thought I'd try and find out what LR are recommending.

The tech bulletin (attached) covering the gasket leaks from this area indicates applying 3mm diameter beads of STC50551 near the "D".

Originally it appears that this part referred to Loctite Forteflex 3951 general purpose polyurethane elastomeric adhesive but this is now a discontinued product.

The online parts suppliers that list this part are now showing images of another Henkel/Loctite product Terostat 8596 which is an automotive glazing adhesive and sealant. The same LR part number is specified for attaching body trim and sealing airboxes when fitting snorkels etc, etc.

Terostat 8596 - Full Product List Teroson - Henkel

So it looks like something like sikaflex 227 is possibly closer to what LR are specifying than an RTV Silicone. My main concern would be that sika 227 is only rated for occasional contact with oils, so additional research is probably warranted.

Add: Sikaflex 255 Extra is a windscreen adhesive with similar properties to the Terostat 8596 so might be a better bet.

cheers
Paul

Just revisiting this:

This is the current listing of recommended sealants for the Td5 from Topix:



STC50550 : Loctite 5900

Typical applications include stamped sheet metal covers (timing covers and oil sumps) where good oil resistance and the ability to withstand high joint-movement is required. It withstands on line, low pressure tests carried out before product begins to cure. The thixotropic nature of LOCTITE® 5900® reduces the migration of liquid product after application to the substrate. LOCTITE® 5900® has an excellent adhesion profile to an outstanding wide variety of plastic substrates, as well as glass, ceramics and metals.

STC50551 : Terostat 8596
STC50552 : Loctite 243

LOCTITE® 243TM is designed for the locking and sealing of threaded fasteners which require normal disassembly with standard hand tools. The product cures when confined in the absence of air between close fitting metal surfaces and prevents loosening and leakage from shock and vibration. Particularly suitable for applications on less active substrates such as stainless steel and plated surfaces, where disassembly with hand tools is required for servicing. The thixotropic nature of LOCTITE® 243TM reduces the migration of liquid product after application to the substrate.

STC3811 : Hylomar 101 (Amine curing RTV silicone sealant - engineering grade)

Hylomar Silicone Sealant 101 is a non-corrosive, low odour Room Temperature Vulcanising (RTV) silicone compound. It is a high performance, engineering grade used in the automotive industry and for general manufacturing. It can also be used for a variety of applications and is particularly suitable for high strength applications in odour sensitive environments.
Hylomar Silicone Sealant 101 has good resistance to oils and aqueous anti-freeze agents
Unlike general-purpose silicone sealants, Hylomar Silicone Sealant 101 contains no solvents and does not give off acetic acid during cure.

STC4600 : Hylomar 3400

Hylomar Gasket 3400 is a modified anaerobic curing, flexible sealant designed to become a Formed in Place (FIP) Gasket when cured. The cured compound has good temperature resistance and high resistance to fretting. The cure is initiated when the compound is in contact with metal ions and in anaerobic conditions.
The cure rate and final strength is dependent on the metals being joined and the temperature at which the component is used. The heat generated by a running engine will accelerate the cure.

So it looks like the recommendation is actually different to what is stated in the Tech Bulletin. The current recommendation given above for the cam cover gasket seal is Loctite 5900 which is a thixotropic RTV flange sealant. This makes more sense than an adhesive sealant.

The recommendations for the Transfer Case are quite different to what I've seen suggested previously on the forum, especially with regard to sealing the covers and output flanges.





cheers
Paul