Cadillac Northstar

Thermalweld is setting a new industry standard for head gasket repairs

Typical sequence of events

  • Often when a Northstar overheats, a mechanic checks the cooling system and finds nothing wrong.
  • With no clear indication as to what’s causing the overheating problem.
  • A mechanic may suggest replacing various cooling system components, like a radiator, water pump or thermostat.
  • Eventually, coolant starts disappearing again and the overheating returns.
  • If this sounds familiar, it is time to get a proper diagnosis. An experienced Thermalweld technician can provide the fastest and most cost effective solution to your problem.
  • Let us help you properly diagnose your Cadillac’s overheating problem and ultimately determine if you have a head gasket problem.
  • To mechanically repair the head bolt problem requires a complete teardown.
  • Drilling out the head bolt threads, installing new sleeves, & replacing the head bolts.
  • Some repair shops refuse to replace a Northstar head gasket.
  • For the ones that will, the starting price is $2,400 up to $4,500.
  • Many suggest “just replace the engine.” Replacing the engine is in the $5,000 to $7,000 range.


Here are the facts!

  • Overheating the engine can damage the head bolt threads on the block.  Once the head bolts lose tension, the head gasket allows combustion chamber gases into the cooling system.
  • Combustion gases will form air pockets in the cooling system, causing thermostat malfunction and overheating.
  • The Northstar engine has a constant air purge system to prevent air lock of the thermostat, but this is overwhelmed when the gasket head bolts fail.
  • Under heavy power demands, the head gasket will allow more gases into the cooling system than under light power demands. That is why the engine may be okay while driving on flat streets but overheats very quickly at freeway speeds or while climbing a steep hill.


Step #1

Install Thermalweld’s Cooling System Modification Kit.

It takes about 15 minutes to install this device in your upper radiator hose. Once installed, it prevents thermostat malfunction and ensures proper coolant flow by minimizing air pocket formation.


Step #2

Thermalweld Treatment

  • Add part A and B to the surge tank
  • Drive immediately (60 mph, third gear, for 5 miles)




Reinforced graphite composite

  • Two-part sealant catalyzed at 2500 RPMs
  • Forms high-strength, flat-surface bond that ensures a tight seal around stretched head bolts
  • New thin-layer deposition technology developed to seal high-volume exhaust leaks.
  • Reinforced with aluminum silicate fiber


Let Thermalweld help you properly diagnose your Cadillac’s overheating problem

and ultimately determine if you have a head gasket problem.

Dave’s Cadillac Audio Review

“My car’s been driving like a dream ever since you worked on it.”

Robert’s Cadillac Audio Review

“It worked good. It helped my car run good.”

If this looks familiar,

it’s time to get a proper diagnosis.

Head Gasket Repair