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Upgrade your Volkswagen GTI 1.8T with the Mishimoto Part Number misMMTS-GTI-99 racing thermostat, designed to enhance your vehicle's cooling efficiency whether on the street or at the track. This high-performance thermostat opens at a lower temperature of approximately 180°F compared to the stock 188.6°F, allowing coolant to circulate earlier in the engine's warm-up cycle. This early activation helps maintain cooler engine temperatures under demanding driving conditions, reducing thermal stress and improving overall engine reliability.
Constructed for precise fitment and reliable operation, the Mishimoto racing thermostat is a direct replacement for the factory component and is compatible with a variety of models including the 1998-2005 Volkswagen Golf, Jetta, and Passat, as well as several Audi A4 and TT models equipped with 1.8T engines. The thermostat features a durable design built to withstand the rigors of racing and high-performance driving, backed by Mishimoto's signature Lifetime Warranty for peace of mind.
Installing this thermostat is a straightforward upgrade that offers tangible benefits in cooling performance, especially during aggressive driving or high-temperature conditions. Its lower activation temperature ensures your engine remains at optimal operating temperatures, helping prevent overheating and potential engine damage. Perfect for enthusiasts seeking improved thermal management or those pushing their vehicles in competitive environments, the Mishimoto 99-05 VW GTI 1.8T racing thermostat is a reliable addition to any performance setup.
Made with quality materials and engineered for precise operation, this thermostat contributes to more consistent engine temperatures, supporting better power delivery and efficiency. Whether upgrading a stock setup or preparing for a track day, this component ensures your vehicle can handle increased thermal loads without compromising performance or durability. Trust Mishimoto’s proven engineering and lifetime warranty to keep your vehicle running cooler and more efficiently over the long term.
Features:
Fitment:
1997 Audi A4 Base
1998 Audi A4 Base
1998 Volkswagen Beetle Base
1998 Volkswagen Golf GL
1998 Volkswagen Golf K2
1998 Volkswagen Jetta GL
1998 Volkswagen Jetta GLS
1998 Volkswagen Jetta GT
1998 Volkswagen Jetta K2
1998 Volkswagen Jetta Wolfsburg Edition
1998 Volkswagen Passat GLS
1999 Audi A4 Base
1999 Volkswagen Beetle GL
1999 Volkswagen Beetle GLS
1999 Volkswagen Beetle GLX
1999 Volkswagen Golf GL
1999 Volkswagen Golf GLS
1999 Volkswagen Golf Wolfsburg Edition
1999 Volkswagen Jetta GL
1999 Volkswagen Jetta GLS
1999 Volkswagen Jetta Wolfsburg Edition
1999 Volkswagen Passat GLS
2000 Audi A4 Base
2000 Volkswagen Beetle GL
2000 Volkswagen Beetle GLS
2000 Volkswagen Beetle GLX
2000 Volkswagen Golf GL
2000 Volkswagen Golf GLS
2000 Volkswagen Golf GTI GLS
2000 Volkswagen Jetta GL
2000 Volkswagen Jetta GLS
2000 Volkswagen Passat GLS
2001 Audi A4 Base
2001 Volkswagen Beetle GL
2001 Volkswagen Beetle GLS
2001 Volkswagen Beetle GLX
2001 Volkswagen Beetle Sport
2001 Volkswagen Golf GL
2001 Volkswagen Golf GLS
2001 Volkswagen Golf GTI GLS
2001 Volkswagen Jetta GL
2001 Volkswagen Jetta GLS
2001 Volkswagen Jetta Wolfsburg Edition
2001 Volkswagen Passat GLS
2002 Volkswagen Beetle GL
2002 Volkswagen Beetle GLS
2002 Volkswagen Beetle GLX
2002 Volkswagen Beetle Sport
2002 Volkswagen Beetle Turbo S
2002 Volkswagen Golf GL
2002 Volkswagen Golf GLS
2002 Volkswagen Golf GTI 1.8T
2002 Volkswagen Jetta GL
2002 Volkswagen Jetta GLS
2002 Volkswagen Passat GLS
2003 Audi TT Base
2003 Volkswagen Beetle GL
2003 Volkswagen Beetle GLS
2003 Volkswagen Beetle GLX
2003 Volkswagen Beetle Turbo S
2003 Volkswagen Golf GL
2003 Volkswagen Golf GLS
2003 Volkswagen Golf GTI 1.8T
2003 Volkswagen Jetta GL
2003 Volkswagen Jetta GLS
2003 Volkswagen Jetta Wolfsburg Edition
2003 Volkswagen Passat GL
2003 Volkswagen Passat GLS
2004 Audi TT Base
2004 Volkswagen Beetle GL
2004 Volkswagen Beetle GLS
2004 Volkswagen Beetle GLX
2004 Volkswagen Beetle Turbo S
2004 Volkswagen Golf GL
2004 Volkswagen Golf GLS
2004 Volkswagen Golf GTI 1.8T
2004 Volkswagen Jetta GL
2004 Volkswagen Jetta GLS
2004 Volkswagen Passat GL
2004 Volkswagen Passat GL TDI
2004 Volkswagen Passat GLS
2004 Volkswagen Passat GLS 4 Motion
2004 Volkswagen Passat GLS TDI
2005 Audi TT Base
2005 Volkswagen Beetle GL
2005 Volkswagen Beetle GLS
2005 Volkswagen Golf GL
2005 Volkswagen Golf GLS
2005 Volkswagen Golf GTI 1.8T
2005 Volkswagen Jetta GL
2005 Volkswagen Jetta GLI
2005 Volkswagen Jetta GLS
2005 Volkswagen Passat GL
2005 Volkswagen Passat GL TDI
2005 Volkswagen Passat GLS
2005 Volkswagen Passat GLS 4 Motion
2005 Volkswagen Passat GLS TDI
2006 Audi TT Base
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All orders are processed and shipped within 24 hours of purchase (excluding weekends and holidays).
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Shipping Coverage
If your package arrives damaged, please notify the delivery driver immediately and contact the shipping carrier to file a claim.
You must report any missing or damaged items within 14 days of delivery.
After this time, we cannot be held responsible for lost or damaged items.
Return Window
You have 30 days from the date of delivery to request a return.
After 30 days, we are unable to accept returns, exchanges, or refund requests.
Eligibility
Items must be returned in their original condition—unused, unwashed, and with all tags and packaging intact.
Certain products may not be eligible for return (e.g., special-order items, customized products, or perishable goods).
Items that have been altered, installed, or modified cannot be returned.
Return Process
Contact our Customer Support team to request a Return Authorization (RMA) before sending items back.
Once your return is approved, you’ll receive instructions on where to send the product.
Customers are responsible for return shipping costs unless the item was defective or incorrect.
Refunds
Refunds are issued to the original payment method once the returned item has been received and inspected.
Please allow 5–10 business days for the refund to appear on your account.
In some cases, a restocking fee may apply (if applicable, this will be disclosed during your return authorization).
