Oem 2.0 bar expansion tank cap is a liability to the cooling system usually resulting in catastrophic failures. I'm using the now recommended 1.4 bar cap, less chance of ruptured hoses & tanks. Bmw now recommends the 1.4 bar! And better peace of mind

Pros: less chance of ruptures, better peace of mind

Cons: liability, catastrophic failures

Vehicle: BMW

OEM Volkswagen › Expansion tank cap

miktip 10 Sep 2025, 14:54

Seal:
Pressure release:

Rating 3.0

Those leaks on your VW... looks to be the expansion tank cap not functioning properly...

Cons: cap not functioning properly

Mahle › Expansion tank cap

Adventurous_Tea6781 13 Mar 2025, 20:24

Pressure release:

Rating 1.0

i got a mahle premium line cap which instantly broke on me not releasing air causing the hoses to get squished, put on the old one and that fixed it.

Cons: instantly broke, hoses squished

MISHIMOTO › Expansion tank cap

nu9u 3 Jul 2022, 21:43

Seal:

Rating 1.0

They sent my friend a cap for a non-m car and it took him a while to figure out the leak was from the brand new cap.

Cons: incorrect cap, caused leak

Vehicle: BMW

Write your review about expansion tank cap

Help others - share your experience with this part.

Part:

Manufacturer:

Make:

Model:

Generation:

Review tone

Positive Negative Neutral

Reviews found: 0

Voted AGAINST engine oil RAVENOL on the rating page

The brake pads Motorcraft has only 4 reviews. Maybe add one more?

The brake fluid OEM Subaru has only 2 reviews. Maybe add one more?

The brake pads Detroit Axle has only 8 reviews. Maybe add one more?

The brake pads OEM Alfa Romeo got the first review!

The brake caliper OEM BMW got the first review!

The brake pads OEM Infiniti got the first review!

For wiper blades PIAA already 100 reviews.

For battery Energizer already 25 reviews.

In the rating best water pump already 12 brands participate!

In the rating best timing belt already 13 brands participate!

In the rating best head gasket already 3 brands participate!

In the auto rating oil filter for Volkswagen Passat already 5 brands participate!

In the auto rating brake pads for Mazda 5 already 10 brands participate!

In the auto rating tires for Subaru Outback already 50 brands participate!

The glow plug Autolite has only 10 votes! Recommend it?

The fender OEM Volkswagen has only 10 votes! Recommend it?

The brake discs Tesla has only 10 votes! Recommend it?

For cabin filter Fram already 25 reviews.

In the rating best flywheel only 4 brands. Do you know another one?

The brake pads OEM Subaru already has 250 votes!

The engine oil AMSOIL already has 1000 votes!

In the rating best CVT transmission only 4 brands. Do you know another one?

The engine radiator MISHIMOTO already has 300 votes!

Voted AGAINST engine oil RED LINE on the rating page

Voted AGAINST engine oil PENNZOIL on the rating page

Owner reviews for expansion tank cap

As of March 2026, PartReview has 6 reviews across 5 manufacturers for expansion tank cap. 5 of them have enough reviews to participate in the ranking of this part.

Popular manufacturers of expansion tank cap

The most popular manufacturers of expansion tank cap on PartReview include:

OEM BMW - 2 reviews. PR Score: not available yet, average rating: 4.5.
MISHIMOTO - 1 review. PR Score: not available yet, average rating: 1.0.
Vernet - 1 review. PR Score: not available yet, average rating: 5.0.
Mahle - 1 review. PR Score: not available yet, average rating: 1.0.
OEM Volkswagen - 1 review. PR Score: not available yet, average rating: 3.0.

Most opinions about performance and characteristics of expansion tank cap are collected on these pages.

Top manufacturers of expansion tank cap

Unfortunately, there are not enough reviews yet to build a ranking. You can help by adding a review.

Comparisons of expansion tank cap manufacturers

There are not enough reviews yet on PartReview to compare expansion tank cap. You can help by adding a review.