---
title: 'Hybrids Are Surprisingly Hard on Engines'
source: 'https://youtube.com/watch?v=3eC5FFoCq4s'
video_id: '3eC5FFoCq4s'
date: 2026-07-28
duration_sec: 745
---

# Hybrids Are Surprisingly Hard on Engines

> Source: [Hybrids Are Surprisingly Hard on Engines](https://youtube.com/watch?v=3eC5FFoCq4s)

## Summary

This video explains why hybrid vehicles are unexpectedly hard on engines due to frequent start-stop cycles, lower operating temperatures causing water and fuel dilution in oil, and the challenges of maintaining proper lubrication. It presents solutions such as using specially formulated oils like Mobil 1 Hybrid, ensuring the engine reaches operating temperature, and regular oil changes.

### Key Points

- **Introduction to Hybrid Engine Challenges** [00:02] — Sponsored by Mobil 1, the video covers three main questions: how hybrids work, why they are hard on engines, and what solutions exist.
- **How Hybrids Work** [00:16] — Hybrids combine a gasoline engine with an electric motor and battery, using regenerative braking to store energy, improving fuel economy.
- **Three Main Challenges** [00:55] — Frequent start-stop cycles, water in oil due to low operating temperatures, and fuel in oil.
- **Frequent Start-Stop Cycles** [01:09] — Engines turn off during deceleration or at stops, saving fuel but causing wear at startup.
- **Majority of Wear at Startup** [01:36] — Mobil 1 estimates 80-90% of engine wear occurs at startup because oil takes 12-15 seconds to circulate fully.
- **Cold Start vs Warm Start** [02:03] — Cold starts are more harmful because oil is thicker; warm starts have oil already flowing and remaining on parts.
- **Anti-Wear Additives** [03:25] — ZDDP (zinc) creates a protective layer on metal components, reducing wear during startup.
- **Water in Oil Problem** [03:38] — Lower engine temperatures in hybrids cause water vapor from combustion to condense in the oil, leading to corrosion and poor lubrication.
- **Hybrid Engine Oil Temperatures** [05:25] — Hybrids run 20-40°C cooler than conventional engines (70°C vs 95-100°C), below water's boiling point, promoting condensation.
- **Emulsion Formation** [06:07] — Water and oil can form an emulsion (mayonnaise-like) that clogs oil filters and passages, causing engine damage.
- **Oil Design Solution** [07:27] — Quality oils use demulsifiers and additives to temporarily absorb water and release it when hot, preventing emulsion.
- **Getting Water Out** [08:10] — Engines must reach at least 100°C to boil off water, expelled via the PCV system. Fuel dilution is also mitigated by high temperatures and oil changes.
- **Mobil 1 Hybrid Oil Guarantee** [09:19] — Mobil 1 Hybrid is guaranteed for 15,000 miles, tested in worst-case scenarios like short trips in humid climates.
- **Oil Formulation Balancing** [10:01] — Formulas balance zinc, corrosion inhibitors, detergents, and demulsifiers to optimize performance for hybrid engines.
- **API SP Certification** [11:19] — API SP rating includes 7 additional tests over SN, covering valve train wear, sludge, chain wear, LSPI, and fuel economy.
- **Hybrid Reliability** [11:46] — With proper maintenance, hybrids like Toyotas can exceed 200,000-300,000 miles.

### Conclusion

Hybrid engines face unique wear challenges due to frequent starts and lower operating temperatures, but these can be mitigated with proper oil formulation (e.g., Mobil 1 Hybrid) and ensuring the engine reaches full operating temperature. With correct maintenance, hybrid reliability remains high.

## Transcript

sponsored by mobile one we're going to be talking about how hybrid vehicles can be surprisingly hard on engines and so we're going to be focusing on three main questions first a quick recap on how hybrids work second why are hybrid
vehicles hard on engines as it's a commonly overlooked Challenge and finally what Solutions exist to combat these challenges starting at the beginning the idea of a hybrid vehicle is very simple so with a traditional
gasoline vehicle you have a fuel tank and that gasoline is sent to an engine which Powers your driven Wheels now with a hybrid it's very similar except you add a few components so now you also have a battery which can send energy to
an electric motor which can also Drive The Driven Wheels electric motors are super efficient and the battery pack allows you to store energy from regenerative braking so this results in vehicles that get better fuel economy
but rightfully you might wonder if an electric motor is actively helping the combust an engine move the vehicle why would this be hard on the engine there's three main challenges we'll discuss lots of start stop Cycles water in the oil
due to lower operating temperatures and similarly fuel in the oil starting with the engine turning on and off frequently this is inherent to the design of hybrids in scenarios such as decelerating going down a hill stopping
at a light or simply when the battery is full the engine can shut off and the electric motors take over now this saves fuel but it also means your engine is turning on and off frequently these frequent start stops can be problematic
as mobile one estimates as much as 80 to 90% of engine wear occurs from engine startup that's because when the engine starts it needs 12 to 15 seconds before the lubricating oil is fully circulating throughout the engine thus preventing
metal on-metal contact and thus minimizing wear now there are several ways you can combat this first off it's important to recognize that the most harmful startup is when it's been sitting for a long time like overnight
and it's starting up dead cold the colder the oil the more challenging it is for it to flow so this Zer W or the cold viscosity grade is very low meaning the oil will flow easily at lower temperatures especially in comparison to
oils like a 5w or a 10w as long as the engine is designed to use it but what light and your engine shuts off then Cuts back on say a minute later well it's still an engine startup which is a challenge but there are numerous reasons
why this isn't as difficult to offer protection here since your engine oil is already warm or hot it flows faster and thus it doesn't take as much time for it to circulate throughout the engine versus a cold start also some of the oil
will still be in place in the needed areas so if I have oil on some aluminum foil as I lift the aluminum foil the oil drains down but it doesn't all immediately flow off if I were to hold this up overnight the vast majority of
the oil would flow to the bottom leaving very little behind but after just a minute or so there's still some oil on there it's like when you change your oil after a minute most of the oil has drained out but if you were to wait even
hours later you can still find oil slowly dripping out all of this meaning if the time between the engine cycling on and off is short it's not as much of a concern since some of the oil remains in place finally you have anti-wear
additives things like zddp or zinc which under high temperatures and pressure creates a protective layer on metal components so next time the engine starts up that zddp acts as a sacrificial barrier to reduce wear from
any metal onm metal contact but there's another really big challenge for hybrid engines and that's water so what causes this so here's an example of what engine oil temperatures look like for a hybrid vehicle versus a traditional gasoline
engine and keep in mind this is after both vehicles have already warmed up which can take longer for hybrids since the engine is running less frequently and so as you can see since the gas engine is always running the engine oil
temperature floats around 95 to 100° now the hybrid will have Cycles temperatures but you can see often it's running at about 70° C because it's
running less often the temperatures consistently remain about 20 to 40° lower on average and yeah this is just my sketchy whiteboard drawing but it's based on real data from mobile 1's testing so what's the problem with lower
average engine temperatures well it makes things like water and fuel dilution a bigger issue water can get into your engine oil in several ways of course if you have a blown head gasket your engine's coolant can leak into the
oil but that's a mechanical failure so let's assume we have a healthy engine all piston cylinder engines have some amount of blowby where combustion gases within the cylinder pass by the piston rings and enter the crank case where
your oil resides water is a byproduct of combustion when you burn fuel you get water and CO2 so this water that ends up passing Pistons is inevitable in environment that means you're adding more moisture into the equation as your
engine pulls in that humid air now if your temperatures aren't high enough this moisture can condense if you're increasing in temperature water boils at 100° C if you're decreasing in temperature water condenses at 100° C so
in the case of the hybrid vehicle we're taking hot water vapor and introduce it to engine oil that's below water's condensation temperature meaning we're now introducing liquid water to the oil this is a problem okay so if I pour
water into this cup with vegetable oil in it you can see they do not mix and no matter how much time you spend trying to mix them once you stop the two liquids will separate and yet if I look at a jar of mayonnaise the two main ingredients
are oil and water but clearly it's not separating into these two separate separating into these two separate components it's one thing mayonnaise so how does it do it well the third main ingredients in mayonnaise is egg and egg
has proteins in it that act as emulsifiers so one part of the egg protein is attracted to oil and another part of the egg protein is attracted to water so when you mix the egg in with the water and the oil you create this
Emulsion where the ingredients don't settle out super cool unfortunately both of these scenarios are terrible for an engine if you have standing water say In Pockets of your cylinder head that can lead to corrosion and water is pretty
terrible as a lubricant so if water ends up circulating between moving Parts you have increased wear but as you can imagine you really really don't want an Emulsion to form in your oil and with engines that never get up to temperature
you can actually see this happen which is a dangerous condition you can plug up the oil filter so it can't clean out contaminants and you can also plug up passages meaning you have limited or no oil flow to certain regions of the
engine and once you stop oil flow you get more wear and this problem only gets worse because once you start having metal wear that means you have abrasive particles flowing through your engine oil and hopefully eventually your oil
filter takes them out but along the way these abrasive particles are now creating more wear so the problem compounds and you end up destroying your engine so what's the solution well you actually want something between these
two extremes so the oil is is designed with base stocks as well as additives that help promote a condition between these two ideally what happens is that as you introduce water into the oil which again is inevitable you want the
oil to capture the water and temporarily absorb it basically the oil will hold on to small amounts of water and have it travel through the engine with the oil until the oil is hot enough that the water boils off and evaporates as an
additive you'll have demulsifiers in the oil which are used to break down oil reduce the likelihood of having mayonnaise in your engine simply put you don't want eggs in your engine oil incredible Insight I know but ultimately
there are limited ways of getting the water out it's important to get the engine temperature high enough so that this water evaporates water boils at 100° C and is expelled from the engine through the PCV system within your
engine you have a vent which allows the positive pressure that builds up within the crank case to be vented to the intake so this gives you a mechanism for allowing that evaporated water to travel back through your intake through the
engine and eventually out the exhaust expelling it from the engine the same logic is true for fuel dilution where lower engine temperatures can promote the two main ways you have of getting this fuel out is bringing the engine up
to temperature and changing the oil and it's worth mentioning things like water and fuel don't immediately disappear once your engine oil reaches say 100° C think about boiling a pot of water once the water reaches the boiling point it
doesn't all immediately evaporate that takes time the other method of getting rid of this water that remains in the oil is of course changing that oil but accumulate too much water within the oil drain interval in the case of mobile one
hybrid this is guaranteed for 15,000 mi this number really comes down to looking at a worst case scenario and ensuring the product still works in that you have a car driven in Key West Florida so you're on a small island
you've got really short travel distances so your engines never really getting up to temperature and it's a really humid environment versus somewhere like Las Vegas where you're traveling further distances getting that engine hot and
it's a dry environment so they have to look at all of the possible scenarios and ensure the product works for the most difficult ones from a formulaic the right balance for the application for example take zinc and corrosion
Inhibitors both of these are surface additives meaning they react with the metal surfaces they come into contact with so both of them are competing for the same real estate if you use too much zddp you reduce the probability that
your anti-corrosion additives interact with the surface and the reverse is true as well the same is true for nonsurface acting additives like detergents dispersants and demulsifiers the proportions you choose mean the oil is
designed to match maximize the probability of addressing certain issues so while this is using many of the same ingredients you'd find in other mobile one oils the proportions of the ingredients differ to suit the
application with more focus on dealing with things like water and fuel dilution in the oil since that's a critical part of protecting hybrid vehicle engines so for a product like this mobile one tells me they started out with about 25
different formulations each of these formulas goes through a series of bench tests which narrows it down to about five top performing formulas then these five formulas end up going into actual engines and a further series of tests
and the result of all of this testing is that you find the formula that works the best and that's what ends up in this bottle now one of the easiest ways to know you're buying a quality oil is to look at the certifications and in
particular here looking at the API SP rating not every oil you can buy at the parts store has this and SP has seven additional industry standardized tests additional industry standardized tests versus SN these tests cover many areas
providing Effectiveness for things like valve train wear sludge protection chain wear protection avoiding lspi engine cleanliness and of course fuel economy it's a no-brainer when buying oil for your car to ensure that what you're
getting has passed the industry's latest tests and this is very easy to check also I think it's worth mentioning Toyota has a deserved reputation of reliability you'll see plenty of the older models of these with over2 200
,000 even 300,000 m on them all that's to say with proper maintenance the reliability of a hybrid vehicle doesn't need to be a major concern hopefully this has provided insight into the unique challenges and solutions facing
hybrid vehicles a big thank you to mobile one for sponsoring the video and providing access to their engineers and thank you all so much for watching if you have any questions or comments feel free to leave them below