Do coil springs eventually go bad? Do they sag or loose strength?

I searched online and there is a lot of misleading information. Some say YES, some say NO with different reason to why YES and why NO.

My Jetta just reached 250k Miles and I'm pretty sure it's got it's original coil springs.

I'm thinking of doing a suspension refresh and I was wondering if the coil springs should be replaced even though they are not broken and they are not rusted too much.

My question is as simple as this!


Thanks !
g.b.

Springs on very early (99.5) TDIs tend to sag. Later cars don't, but if your car is a very early 2000 this may be the case. They also break: ends break off the front and rear springs, although rears breaking is more common.

If your car sits lower it may be because of worn suspension and mounts (especially the fronts) than springs. But look at the springs when you take the car apart to see if they're OK. Depending on where you are in Canada, after 17 years in a harsh climate you may want to replace them anyway.

As a material coil springs do not wear out (well maybe decades). In real life they often suffer from delamination where thin layers separate, generally as rust, reducing material section. So like IBW says, 17 years on salted roads you may be looking at a worn component.

I agree.
I have replaced springs on past vehicles with no benefit.
On the Jetta I replaced the rear with taller dual rate springs to give lift and reduce sagging under load.
Look at the springs really good and see if they're delaminating.
If there is any delamination replace them, they will break.
For the cost of replacement and the size of the job make a decision before getting into the work.
You can get a good price for OEM and OEM upgrade springs.
Unless you tow a lot their likely good and rears tend to fail before the front due to more drastic change in load and more contact with water/salt/dirt.
Fronts tend to last longer because the load change is minimal and they are placed higher reducing the attack by the elements.
If they're good you should paint them so they last.

Most (all?) springs have protective coatings on them. If there's any signs of this material coming off (and it usually is at the contact points at the top or bottom) then they're already under attack from rust. Rust will likely be a more likely outcome, though all metal will eventually suffer from fatigue. In my mind since it's a lot of work to do struts I find a $100 or so for new springs to be a no-brainer.

Greater contributor to sag is aged rubber mounts.

Do yourself a favor and get polyurethane upper mounts. I swapped in track density and after only a couple years they are squashed and squeaking.

Springs? Usually last a LONG long time, unless the design over-flexes the material, or the material is inferior in some way. However, I am extremely fond of heavier duty springs and am running the cheapo Moog VR6 springs with no regrets.

Where do i find those polyurethane mounts? I may check them out !
g.b.

guillaumeber said:

Where do i find those polyurethane mounts? I may check them out !
g.b.

Click to expand...

I have a set in mine - steering is much improved, cabin is still quiet.
https://www.amazon.com/gp/product/B00BGF83NY

They are available from a variety of vendors. I got mine off an Audi specialist on E-bay.

Polyurethane fixes a design flaw. Putting rubber in is simply a mistake. I only put rubber back in because poly wasn't available at the time.

Rubber strut mounts are fine. They are a wear item, I usually replace them every 3-5 years depending on how much use they get. But dampers don't last much longer than that. Lots of TDI owners keep worn suspension in their cars way too long.

One can change the mounts in-place (without removing the struts), so it's really not a big deal to replace them.

I'd figure that driving conditions have a lot of say in how long things hold up. I drive mostly highway, good road surfaces, so my suspension should last longer than for most. Wife's old Mazda 5 had a strut go bad with only about 35k miles on it: that car was subjected to Vancouver BC roads

When I was getting my front struts replaced last year both springs were broken. Not sagging. Broken. They were probably original springs because the struts appeared to have been factory original.