[stone_cold]

VW Vento Trendline petrol 2011 dropping power around 1000RPM mainly in summers. Got head gasket replaced twice (once in October 2022 and then in May 2024) without any improvement. Looking for advices.

TL;DR
I bought a VW Vento Trendline petrol 2011 make 2012 registered in October 2017 from a dealer in New Delhi. I was in a job in New Delhi since 2014 and was looking for the first car with my salary with a very limited budget. One of my colleagues had VW Vento in his family and was himself driving VW Polo and was always very appreciative of both these cars which influenced my decision of buying one.

The car was supposed to run mostly in my home town in Rajasthan. I was initially very happy with my possession and took the car regularly for the services to the authorised service center in Jaipur as there wasn't a service center at my home town even though the service center charged hefty amounts for basic services sometimes in the range of 20,000 - 25,000. I started getting the car serviced at local mechanic in my home town due to the burden of taking the car to Jaipur and paying hefty amounts without any statisfactory explanation from the service center.

Fast forward to 2022, the car started giving over-heating issues. Upon taking to the same mechanic who was doing the regular service of the car I was told that the head gasket needs a replacement. The car had completely stalled and I decided to trust the mechanic and gave him a go ahead. He kept the car for 10 days and replaced the head gasket charging 35,000 for it and some other services performed during the work like cleaning of radiator. The replacement was done in October 2022 and the car drove quite well for the entire winter but started giving issues like power drop in April 2023. I took it to the same mechanic, he did some analysis, kept the car for a day and gave it back to me saying everything should be fine now only to find out it wasn't. I drove very less during the summers and it worked alright during the winters 2023. Now, as soon as the temprature started rising in 2024, the car again started giving issues of power drop while driving, it would seem like there is no fuel supply to the engine whenever the issue occurred. This time I took it to a mechanic in Jaipur as I knew that it would be extremely costly to get the car fixed at the service center.

The mechanic in Jaipur analysed the car and came to the conclusion that the head gasket was blown. He suggested me to replace the head gasket. I gave him the complete history of the car and he was sure that it was a head gasket issue and replacing it would solve the problem with the car. I wanted to keep this car forever and therefore decided to go ahead with his suggestion. He replaced the gasket and invited me for a test drive. While driving I noticed the same issue again and again, the mechanic was of the opinion that the issue should go away once I drive it a few hundred kms. I took the car from him and had drove just 10kms and the car completely stalled. I called him, he came to tow the car. By the time he came half an hour had passed and the car started when he turned the ignition on. I asked him to drive the car to his garage so that he could himself see the issue. The car was completely loosing power by the time it reached his garage. He asked for more time from me and kept the car with himself. In his next diagnosis he found that there was significant at the fuel pump inlet in the tank. He cleaned it and test drove several kilometers and finally asked me to pickup the car. My brother went to get the car and he noticed slight jerks while driving which the mechanic again said would get fixed in some kms. We got the car to home and now the car is again giving the same issue of dropping the power like completely fuel supply cutoff around 1000rpm when you have driven it for 5-10kms.

Has someone else also faced similar issues in a Vento? What are your suggestions? What should I do next? I called the mechanic in Jaipur and he said that as everything has been checked except for the radiator, he would like to have a look at the radiator.

[AMG Power]

Originally Posted by stone_cold

VW I started getting the car serviced at local mechanic in my home town due to the burden of taking the car to Jaipur and paying hefty amounts without any statisfactory explanation from the service center.

Your intention to save costs has resulted in just the opposite along with a damaged car. You would have been far better off with the ASC.

When you take your car to an FNG you need to either (a) be very sure of his capabilities wrt your car or (b) you need to know your car extremely well.

You have been ripped off by FNG 1 & 2. It looks like it may be very expensive to repair the car and may need replacement of a half engine block.

Your options are (1) take it back to the ASC to ascertain the extent of damage caused by the various FNG’s and based on the cost decide whether you want to go ahead with it or (2) if it is too expensive, sell the car.

[Bsilver]

Originally Posted by stone_cold

What are your suggestions? What should I do next? I called the mechanic in Jaipur and he said that as everything has been checked except for the radiator, he would like to have a look at the radiator.

Did the first mechanic who replaced your head gasket check your water pump?
If he has not checked the water pump, which is easier to examine than examining a head gasket, then no matter how many gaskets you replace they will be blowing as the water pump is faulty, and the question is did he replace it with a OEM one. As per my personal mindset, one should never compromise on engine/powertrain components as the non OEMs will definitely hinder in the longevity of the vehicle.

The logic behind the overheating (as per best of my knowledge, I may be wrong), is the water pump. Water pump circulates the coolant in the system through the radiator and into the galleries in the engine. The engine is divided into 2 parts, the one containing the cylinders, pistons, and second one the head comprising the valves, camshafts, plugs. And the head gasket is the one sandwiched between these two parts of the engine, and is subjected to extreme heat from the combustion process. The gasket is designed to tolerate certain limits, now what is the correlation with water pump?
The water pump circulates the coolant through the galleries, with the radiator at the front of the vehicle, so if one of the components in the cooling system is faulty(can be more than one, as hard to tell without a physical inspection), then the temperatures will rise over the tolerance limits and cause the engine block to expand, and blowing the gasket. This is one part of the story.
The second part is that, if the gasket is blown the coolant will enter the cylinders which is not a very pleasant thing for the engine. And the resultant to this is overheating issues as the water pump has not got enough coolant to circulate, secondly it will cause white smoke from the exhaust of the vehicle.

And one more explanation for the loss of power(unless we know where the blow is), if the gasket is damaged in between adjacent cylinders, it will cause one cylinder compression to leak into other, and the result is overall loss of power in the vehicle. This might be a logical explanation as to why the car gives you the issue after driving 5kms. This distance is more than enough for the engine coolant to warm up, as well as go above the tolerance limit. This can partly explain why your car started when the mechanic attempted to turn it on after a period of half hour.

Never accept the words "it will get better with driving", it is one of the sentences misused by mechanics who cannot do a good job. If the matters are not correct in the first place, then they will in fact "get worse with driving", these things are not like any ECU learning mechanism that'll get better with driving.

As far as the suggestions(NOTE: Giving them without knowing the vehicle physically, and as per OP), I will make you a flow chart for it.
1. Check the water pump first. A easy way to check the water pump is, undo the cap when the engine is cold, start the vehicle. The coolant tank in Vento has a return line to it at the top right. Check whether the coolant is returning from that line, you can see it dripping back into the tank. If you are not able to see it, rev it till around 2500rpm, and this will spin the water pump faster increasing the flow, and now you shall be able to see the coolant returning to the tank. Do this on a cold engine, if you do on a hot engine, you'll end up with severe burns. If you are not able to see coolant returning back, either the water pump at the first place is not flowing the coolant, or some line is blocked( which is not likely as it would've blown the pipes by now due to the block).
2. If good, check the radiator functioning along with the pipes for any leakages. Do check the thermostat as well. Make sure the radiator is clean, and has not collected grime.
3. If good, then check the head gasket, and if blown, then you will probably need to assess the internals for the damage, which would turn out really expensive if gone wrong.
4. Check the fuel pump, might be someone has touched it during inspection, or diagnosis. If the fuel pump is not fit in the correct orientation it will not provide the required pressure to HPFP to operate and a loss of power. I have a post on this on my profile. Link here:https://www.team-bhp.com/forum/india...lership-3.html (Help needed | Rat damage to my car & ECM damaged | Insurance company blames dealership)
You could do the following, and hopefully you would get it back running. I have answered as per best of my knowledge. Happy Motoring!

[stone_cold]

Originally Posted by Bsilver

Did the first mechanic who replaced your head gasket check your water pump?
If he has not checked the water pump, which is easier to examine than examining a head gasket, then no matter how many gaskets you replace they will be blowing as the water pump is faulty, and the question is did he replace it with a OEM one. As per my personal mindset, one should never compromise on engine/powertrain components as the non OEMs will definitely hinder in the longevity of the vehicle.
…
You could do the following, and hopefully you would get it back running. I have answered as per best of my knowledge. Happy Motoring!

Thanks for the detailed reply and the flow chart. Following are the answers to some of your questions:
1. Yes, the first mechanic did check the water pump and it was fine.
2. First mechanic had gotten the radiator cleaned.
3. Second mechanic cleaned the fuel pump during the most recent work on the car as he also suspected the inadequete fuel supply. Also, the issue becomes more prominent during summers and power drops immediately at 1000RPM.
4. I myself have done the inspection related to the water pump. The water pump successfully returns the coolant to the coolant tank but it gets pretty hot very quickly.
5. I will get the thermostat checked.

Once again thanks for taking time out to write the detailed reply.

[Bsilver]

Originally Posted by stone_cold

3. Second mechanic cleaned the fuel pump during the most recent work on the car as he also suspected the inadequate fuel supply. Also, the issue becomes more prominent during summers and power drops immediately at 1000RPM.
Once again thanks for taking time out to write the detailed reply.

Since you have ruled out most of the issue with the coolant circulation, one thing left is thermostat, please get it checked, if fine, then the entire cooling system is working correctly.
Then if the issue still persists then, check the fuel supply to the engine. There is way to log the vehicle fuel system via VCDS, or any FNG would log it using their tools. This method would give you if the fuel pressure at the HPFP is correct or not. For VCDS, the steps are:
1. Go to the Engine module.
2. Click on advanced measured value blocks.
3. From there select: I. Engine Speed in rpm II. Fuel pressure specified value III. Fuel pressure actual value.
4. Click on Turbo on the top, this increases the sample rate.
5. Click on Save and choose the destination, and then do not press log.
6. Choose a very very safe place to do this and make sure their is no traffic or you are not hurting anyone. Go till third gear and from a lower RPM say about 950 or so, click log and floor the throttle, continue for around 8-10 seconds(as your car will not reach redline with the issue it has). Stop logging.

Once you have the log with you, then it will be in form of a table, convert it to a graph using online software. From here you can get to know whether the fuel system is actually functioning properly or not. I will attach a fuel log of my vehicle here:

As you can see the specified value is the pressure value which the ECU is requesting the fuel pump to deliver, and if the fuel system is good all the way from LPFP, Filter, HPFP, into the Rail. Then you will have a graph something like the above one.
Actual value is the pressure value which the pump is able to deliver, and if this has too much deviation from the requested then you can conclude that the fuel system is faulty, and further investigation is needed. If all fine then you can again conclude that the fuel system is not the cause of the issue. So by doing this you will be able to rule out that the cooling system and the fuel system are not causing the issue. Plus it becomes easier to do further study if you start rejecting the things not causing the problem. I would suggest you to do this if the thermostat is fine as it is not causing the issue. Hope this adds to the explanation as well. Happy Motoring!

[stone_cold]

@Bsilver Thanks for your efforts and providing the detailed steps to diagnose the issue. I will go through the steps and update you.

I was also skeptical of the fuel supply based on my discussions with chatGPT but overlooked it because the issue is prominent in summers. chatGPT also suggested that it is possible that lack of fuel supply can lead to engine running lean and thus generating more heat which in turn can impact the efficiency of fuel system. Do you think it can be a possibility?

I will do the following:
1. Check thermostat
2. Log fuel pressure
3. Get the radiator checked (once again as it was last checked with mechanic 1)

[Bsilver]

Originally Posted by stone_cold

chatGPT also suggested that it is possible that lack of fuel supply can lead to engine running lean and thus generating more heat which in turn can impact the efficiency of fuel system. Do you think it can be a possibility?

This is not the apt way to convey it. The engine runs lean mainly because the fuel system is faulty, and it won't impact the fuel system as it is already compromised and not able to deliver. There may be some other reasons for the engine running lean, like vacuum leaks, faulty O2 sensor, clogged injectors. All these things will show up in a scan, if you have one then you can see for any errors.
For the AFR to be lean, means there is not enough fuel to burn the air in the cylinder, and directly relates to the fuel system. The chemistry behind this:
The fuel (petrol in this case) has a higher specific heat capacity as compared to air. So when the air fuel mixture is introduced in the combustion chamber it is entering at a lower temperature than the temperature of the engine. The walls of the cylinder (combustion chamber) are at a higher temperature than the introduced mixture. And as we know the heat flows from higher temperature region to lower, the heat is flowing from the engine to the mixture and going out from the exhaust manifold after the cycle is complete. So more heat is taken away from the residual mixture, and as a result cools the engine. Now this is the chemistry part of it.
When the fuel is not present in the right stoichiometry, then firstly your engine would not run properly, secondly since there are less components of fuel present, there is not much heat transfer happening in between the mixture and the engine, so the heat stays within the engine itself, resulting in an overheat, and a performance compromise. If I am wrong in any part of the explanation, happy to welcome corrections. This is a reason why tuners use a little rich fuel mixture when pushing more power, so that the fuel acts as a coolant. All this will negatively impact the turbine wheel as well, because of the higher EGTs, and it will hamper the longevity of the engine. I hope this helps. Cheers!

[Tgo]

Originally Posted by stone_cold

Has someone else also faced similar issues in a Vento? What are your suggestions? What should I do next? I called the mechanic in Jaipur and he said that as everything has been checked except for the radiator, he would like to have a look at the radiator.

Older more complicated cars maybe the local mechanics are diagnosing it wrong. Is this a diesel or petrol?

I feel like its a evap canister related issue. Just a guess as it can cause improper fuel delivery.

[AKSarkar1]

Others have already given a very technical answer which I agree with hence wouldn’t repeat the same points. The garage that you have taken your car to isn’t a FNG it is an ENG (Evil Neighbourhood Garage), they have clearly ripped you off.

However, being an owner of 4+ cars from the Vento and Polo family I think it is time to move on. Giving the continuous repairs on the engine and the age of the car I would say that you will be better off buying a new or pre-loved car.

Also saying this because you mentioned that you have a trendline Vento and life has changed a lot since the 2011 Trendline model, I would say that you should swap this car for a newer version of the Vento or Polo if the budget permits. I am assuming that since you have hung onto the car for a while now you must be liking VW quality and feel, but that is not enough for you to sacrifice your time and peace of mind.

[chinmaypillay]

It seems to be a clear case of rip off without analysing the actual cause of the issue.
I would advise to dispose off the vehicle and cut your losses however painful it is.

Once these issues start, it will only get worse with time and become a sunk cost.
Better to dispose it and get a newer vehicle which will be less of a headache.

And going forward, please take a second opinion of the issue before committing to the repairs to avoid unnecessary rip offs.

As a last resort, ask the mechanic to clearly inspect the fuel filter, injectors and Turbo. Filters can also be checked.

Once that is done, please get rid of it

[Blow Horn Ok]

If you really want to retain the car, get it checked by some competent Mechanic. There are plenty of youtuber mechanics in NCR region.

I guess the head must have been damaged after many sessions of overheating.

[pv5]

I had faced a similar issue in my vento(2 months back) and it lead to catastrophic failure. The fuel and coolant mixed, the head got damaged and valves got damaged. All this happened on a road-trip. The sensors only kicked in very late and i guess the damage was already done by then. The loss of power was the first sign. Also please don't drive for longer duration, it could damage the head. If you decide to take it to another mechanic, please take it by a flat-bed & not drive.

[neeladri]

Have a look at the Engine Vaccuum Pump. More explanation in the url provided.

https://www.carfinite.com/vacuum-pump-101/

All the issues mentioned seem to be resultant not the cause of the issue.
All the best !

PS: I still own a March 2011 1.6 Petrol MPI Automatic. It’s my family workhorse driven by our family driver.

[Jeroen]

Originally Posted by stone_cold

Fast forward to 2022, the car started giving over-heating issues..

Let’s get back to basics. What are the exact symptoms that led you to believe the engine is overheating?

When I read all of this I am not so sure.

Jeroen

[stone_cold]

Originally Posted by neeladri

Have a look at the Engine Vaccuum Pump. More explanation in the url provided.

https://www.carfinite.com/vacuum-pump-101/
.

Hi

Thanks for the link. What a great knowledge resource the website is!!

I am not sure if there is a vaccum pump in VW Vento Petrol 2011 make.