What an Engine Gasket Kit Contains, and Why the Full Kit Matters
An engine gasket kit is not a single component; it is a complete assembly of sealing components that covers every joint, passage, and interface in a diesel engine that requires a seal to function correctly. The scope of a kit varies depending on whether it is a head gasket kit, a top-end kit, or a full engine rebuild kit, but the principle is consistent across all three: every seal in the relevant assembly should be replaced at the same time.
A complete engine gasket and rebuild kit typically includes:
-
Head gasket — the primary combustion seal between the cylinder head and engine block, the most critical single component in the kit
-
Head bolt set — torque-to-yield head bolts on most modern diesel engines are single-use and must always be replaced with a new head gasket
-
Valve stem seals — control oil consumption through the valve guides, and must be replaced whenever the head is removed
-
Intake and exhaust manifold gaskets — seal the combustion charge and exhaust gas pathways into and out of the cylinder head
-
Oil gallery plugs and seals — seal the internal oil passages that route lubricant through the block and head
-
Coolant passage O-rings and seals — maintain coolant containment through every passage junction in the engine
-
Crankshaft front and rear main seals — on a full rebuild kit, these are included to address the most common sources of external oil leaks
-
Sump gasket — seals the oil pan to the bottom of the engine block
Sourcing these components individually across multiple suppliers introduces the risk of specification mismatches, missed components, and delays that stop a rebuild mid-way through. A consolidated rebuild kit from Imara Engineering eliminates all three risks in a single order.
CAT Head Gasket Kits, C15, 3406E, 3306 & Full Platform Coverage
Caterpillar diesel engines represent the highest demand for gasket kits and rebuild kits across our entire range. The CAT C15 and particularly the C15 ACERT is the single most frequently overhauled engine in our customer base, driven by the known head gasket and sealing issues this platform experiences under sustained high-load operation. The 3406 family is similarly high-demand, reflecting the enormous volume of these engines still in active heavy-duty service globally.
Our CAT head gasket kits range covers:
-
CAT C15 head gasket kit — available for both the standard C15 and the C15 ACERT variant, with correct gasket compound and head bolt specification for each
-
CAT 3406E head gasket — one of the highest-demand head gaskets in our range, requiring exact compound and thickness specification for correct compression sealing
-
CAT 3406B head gasket — the earlier 3406 variant with a different head bolt specification from the 3406E — our team confirms the correct variant for your engine serial number
-
CAT 3306 head gasket — a widely deployed legacy platform with strong ongoing gasket kit demand
-
CAT C13 head gasket — deployed across large excavators and heavy plant across all major markets
-
CAT C7 head gasket — a mid-range CAT platform with strong head gasket replacement demand at high engine hours
-
CAT 3208 head gasket — a reliable multi-application platform with broad gasket kit availability in our range
Every CAT head gasket kit is supplied with the correct head bolt set for the platform torque-to-yield bolts are single-use and must be replaced with every head gasket.
CAT Engine Rebuild Kits & Overhaul Kits, Complete Overhaul in One Order
For operators committing to a full engine overhaul, not just a top-end repair, a complete engine rebuild kit is the most efficient and reliable way to source every sealing component required for the job. At Imara Engineering, our CAT engine rebuild kits are assembled to cover everything from the head gasket down to the rear main seal, eliminating the risk of incomplete sourcing on a complex overhaul.
Our CAT engine rebuild kits and overhaul kits cover:
-
CAT C15 rebuild kit & CAT C15 overhaul kit — the highest-demand rebuild kit in our range, available for both the standard C15 and the ACERT variant, with variant-specific component specifications
-
CAT 3406E rebuild kit — a complete overhaul kit for one of the most rebuilt CAT engines in existence, covering every sealing surface in the engine from head to sump
-
CAT 3406B rebuild kit — the earlier 3406 variant with platform-specific gasket compound and seal specifications
-
CAT 3306 rebuild kit — a widely demanded legacy platform overhaul kit with strong availability in our range
-
CAT C7 rebuild kit — a mid-range CAT overhaul kit for the full engine rebuild, including head gasket, valve seals, and crankshaft seals
-
CAT 3208 rebuild kit — covering the full sealing component set for a complete 3208 engine overhaul
-
CAT C12 & C13 rebuild kits — complete overhaul kits for high-torque mid-range CAT platforms
Every rebuild kit is supplied as a complete set, not piecemeal components that require cross-checking for completeness. Our team verifies the correct kit specification against your engine serial number before every order ships.
Understanding Head Gasket Failure, The Most Costly Sealing Failure in Diesel Engines
The head gasket is the single most critical sealing component in any diesel engine. It simultaneously seals combustion pressure of over 2,000 psi on every firing cycle, maintains separation between the coolant passages and the combustion chamber, and keeps the engine oil galleries isolated from both coolant and combustion gases. When a head gasket fails, all three of these functions break down at once.
Common causes of head gasket failure on heavy diesel engines include:
-
Overheating — sustained or sudden overheating is the most common trigger for head gasket failure. Thermal expansion warps the cylinder head surface and crushes the gasket beyond its recoverable sealing range
-
Incorrect installation — head gaskets installed without a resurfaced or verified flat cylinder head surface will fail at the high spots within hours of operation
-
Incorrect torque sequence — head bolts must be torqued in a specific sequence and to exact specifications. Out-of-sequence or under-torqued bolts create an uneven clamping load that causes localised gasket failure
-
Single-use bolts reused — torque-to-yield head bolts stretch on first use and lose their clamping load if reused. Reusing old head bolts on a new gasket is one of the most common causes of repeat head gasket failure
-
Wrong gasket specification — an incorrect gasket thickness or compound changes the engine's compression ratio and sealing characteristics, risking both performance issues and early failure
At Imara Engineering, every head gasket kit we supply includes the correct head bolt set, the correct gasket compound for the platform, and the correct torque specification documentation, removing the most common causes of re-failure from the outset.
What to Replace at the Same Time as Your Gasket Kit
A gasket kit replacement is most effective when the components that interface directly with the gaskets are in the correct serviceable condition at the same time. Fitting new gaskets to worn or out-of-specification mating surfaces is one of the most common causes of repeat overhaul failure on heavy diesel engines.
At Imara Engineering, we recommend sourcing the following alongside your gasket kit:
-
Cylinder head — if the existing head is cracked, warped, or porous, a new gasket against a failed head will not hold. Check our Cylinder Heads range for full CAT and Cummins platform coverage.
-
Cylinder liners — on a full engine rebuild, new liner lower seals are included in the rebuild kit. If liners are being replaced, the liner O-rings and seals must match the new liner specification.
-
Pistons and piston rings — on a full top-end overhaul, valve stem seals from the gasket kit are installed at the same time as piston ring replacement. Browse our Pistons & Rings range for matched platform coverage.
-
Engine assembly components — if the overhaul is being carried out to avoid a full engine assembly replacement, ensuring all internal components meet OEM specification before the rebuild kit is installed protects the investment in the overhaul.
Our team can consolidate all components into a single order, reducing sourcing administration and eliminating the risk of a missing component halting your rebuild.
Why Source Your Gasket Kits from Imara Engineering?
Workshop managers and fleet operators across Australia, North America, Canada, and globally choose Imara Engineering for gasket kits and rebuild kits because the consequences of an incorrect or incomplete sealing kit are too significant to compromise on specification or sourcing quality.
-
OEM Sealing Specifications — Gasket compound formulation, head bolt grade, and stretch specification, and O-ring dimensions all matched to OEM standards for your specific engine variant. The right spec is not optional in this category.
-
Complete Kits, Not Partial Sets — Every rebuild kit is supplied as a complete, consolidated set. No missing components, no back-ordering individual seals mid-rebuild.
-
Confirmed Fitment Before Dispatch — C15 or C15 ACERT, 3406E or 3406B, the correct kit variant is confirmed against your engine serial number before every order ships. The wrong gasket compound or bolt specification on a head gasket is a re-failure waiting to happen.
-
Paired Supply Available — Cylinder heads, cylinder liners, pistons, and rings available alongside your gasket kit in a single consolidated order for a complete overhaul supply.
-
Fast Worldwide Shipping — Dispatching to Australia, USA, Canada, and internationally with full tracking and fast turnaround on all in-stock items.
