"Asking for a Friend" 2000's Kia Rio Starting Issue

So, totally unrelated to Tacoma's, but there are a lot of gearheads on here that might be able to offer some diagnostic tips.

2008 or so Kia Rio with ~200000 km (125k mi). Friend has owned the vehicle for at least a year or more and it has always had trouble starting. Battery has been replaced not long ago and seems okay with cursory voltage checks both sitting and during cranking.

Until the recent cold, the car would crank easily for a bit then seem like there was significant resistance (like the starter isn't turning the engine anymore) but after a second or so it would suddenly continue and fire up. With the recent cold weather it won't start even with a booster pack and long cranking time.

I need to confirm, but it almost seems like there's a pattern based on the 4 cylinders - like 3 cylinders move easily then one has more resistance.

The starter costs around $200 CAD and doesn't look like a lot of fun to replace. I'm not convinced that the starter is defective though.

This vehicle has also had some overheating issues in the past and I'm thinking that maybe the issue is related. Is it reasonable to think maybe a head gasket and coolant into one cylinder causing this?

I'd appreciate some theories and suggestions for things to check that are reasonably easy to do. I'm already planning to pull the spark plugs once it warms up here.

Thanks!

 

Could be leaking coolant into the cylinders… but if that was the case you would probably be seeing a lot of coolant loss and smoking on cold start

 

Maybe try a compression check on all four cylinders to see if there is any great degree of variance from any of them?

 

Might sound dumb but also check the starter relay. I had an old shitbox car that did weird things like this and for some reason the starter relay would corrode faster that other contacts in the fuse box. My theory was the fuse box plastic was old and degraded from heat cycles making the contacts inside flex during heat/cold cycles and work its way loose allowing excess moisture in. Brushed off and bent contacts for tighter fit and it would solve the problem for a period of time.

Worst case is that’s not your gremlin and you lost 5 minutes of your life but gain peace of mind that it’s not the relay.