Hello,

This is for a 2002 V70 Station Wagon. Base Model. 168K miles.

So this is what happened:

Few days ago I removed the coolant from the reserve tank (Side plastic tank) with a turkey paster. I was too lazy to do a complete flush. When the level dropped last time I added some Distilled Water since I did not have the correct HOAT Coolant.

I bought some Prestone Coolant that says it is HOAT combatiable.

After I sucked some of the old coolant out of the tank I added concentrated New coolant.

Today I drove 150 miles mostly on the freeway, it was a very hot day so the AC was on. NO issues.

On the way home, the Low Coolant warning light came on. NO over heating or anything.

I pulled over and added Water from one of those Drinking Water bottles you get from the store....that is all I had. In case it makes any difference I left the car running, I think AC was off. I opened the Coolant tank slowly and it was very low, to the level of the float. I added the water and closed it up.

Got in the car and now the check engine light was ON. Never been on before.

I checked all the caps, gas cap, oil and other fluid levels, transmission fluid...all was Ok.

So the first question here is this: Is it normal for the Coolant level to go down to LOW (Remember I filled it few days ago with Coolant), basically after about 160 miles of highway driving, there was some slowing down in traffic (With the AC ON), Hot day.

I could not see any coolant leaks, old hoses,...etc. Everything seem Ok. Oil Cap is NOT milky or frothy.

I drove the car and noticed the car is sluggish with a slight vibration.

The Warning: "Try Slow Down or Shift up" came up on the dash.

I went to O'reilys auto store, borrowed a Scanner. The store guy came out with it and scanned the codes. It came out "Misfiring on Cylinder 4".

The guy from the store tells me, it is the Ignition coil in Cylinder 4 needs replacing. To replace it and it will fix the problem. We reset the code and the check engine light went away for now.

So I have 150 miles driving to get home.

I drove the car and still had the same issue of less power...etc.

The check engine light would come on, flash few times then disappear. Same with the Warning statement "Try slow down....etc".

In traffic we were going 25 MPH. Going down hill, I would put the transmission in Neutral as to not stress the engine. Other times I kept the RPM under 2000, with a speed of about 53 MPH, I used Cruise Control (It took forever to get home).

When there is a climb, the light and warning would come on which told me the engine was being stressed, so I would lower the speed. I also tried going to 4th and 3rd gears which would increase the RPM.

Anyway, I made it home.

My question is: Is me driving the car 150 miles with this misfire caused ANY damage to the engine or transmission ??

2- I have a NEW Bosch Ignition coil which I will install. I assume #4 Cylinder is counting away from the Timing Belt, where # 1 Cylinder is the closest to the Timing belt ?

3- Is there an easy way to test these ignition coils ?

4- Is it correct to assume that since One Coil is gone bad that the rest will soon follow therefore ALL of them should be replaced ?

5- Volvo and Bosch coils are Expensive. Are the cheaper brands OK to use or do they last a month or 2 then die ?

6- Which brands of Ignition Coils you guys know to be reliable ?

Finally, is it a good idea to replace ALL the spark plugs too ?

I appreciate the assistance.

Thank you.

 

too many words-

If you have a missfire code, and you think it's coil related, move the offending coil to another cylinder, clear the codes, drive again, see if code moves to another cylinder. (to prove the coil is bad, before purchasing a part you might not need) Bad spark plugs can kill coils also - make sure you use the correct plugs and change them at appropriate intervals to avoid damaging your coils. Always use the best quality parts you can afford.

 

I didn't use "Too many words" for nothing. There is a reason as I was wondering if the 2 issues are related....the misfire coming after the coolant warning light. And the other questions are self explanatory.

The car does have the correct spark plugs but I will start with looking at #4 coil and plug and go from there. I am still wondering about the rest of my questions and that is why I posted them.

Thank you.

 

Hi,

Coolant level in the expansion tank should in normal operation and when up to temperature reduce and show as low. If coolant is added at this time, is it not possible that it then could be overfilled, which might cause over-pressure within the system and consequently a risk that it might ‘blow off’. This may happen not only at the design point, mainly a sprung valve then tube to atmosphere but also at a weak point in the system which could lead to issues, which may manifest in ways similar to that which you indicate.

Regarding coils, swap them over in order to chase the fault, thereby confirming (or not) the identity of the problem one. Replacing, well you get what you pay for, I suggest if possible sourcing known to work good quality secondhand ones in order to reduce costs.

Spark plugs; It is known that this engine is intolerant of low quality replacements and the accepted good practice (on any engine) is to replace all at the same time.

Kind Rgds and Good luck,

Mick.

 

a few thoughts - if you tried doing a drain fill for the coolant system, its possible the system needed to be burped to remove an air pocket. refill and monitor. If the car overheated or ran hot, you may have other issues to investigate - thermostat, coolant temp sensor etc. If you see the level go down again - well the coolant needs to be going somewhere.. look for signs of a leak (hoses, reservoir) or signs of a head gasket issue. As to CEL and misfires - did you get a generic misfire or something specifc to one cylinder (ie P0300 vs say P0304)? Assuming you got a P0304 only, then as hoonk suggested you probably have one bad coil and you can try swapping positions. As to buying replacement parts, there's not a lot of rocket science in a coil. Usually when they fail its because the insulator is leaking some current (ie say there's crack so its not hot enough to fully spark under load. Its not like they wear out so I'd just replace the one that failed and consider keeping a spare in your parts box. The other fault area is the wire harness to the coils so you should inspect the connectors to the coils as well.

Regarding your questions - yes #1 cylinder is closest to the timing belt. Bosch coils should be fine, I've also used Autozone Durlast in a pinch (not sure who their supplier is ) and that has lasted 5+ years no issues. Check Volvo friendly stores like IPD and FCP to see what OEM/aftermarket brands they carry for options. If you want to stick with Genuine Volvo, check out Tasca Parts - they have the best prices I've found for dealer parts. As for the plugs, check your owners manual (they can be found online as well) for the service interval but I believe plugs should be good for 60K miles. Here I would recommend genuine Volvo as they come pre-gapped and properly sized. More is not better for plugs (ie Iridium triple electrode bla bla bla) to keep a Volvo engine happy.

 

I lament with you. I have a similar problem. I’m trying to get through smog and I’m already on my second extension to get tags. I carry a scanner in my car now just so I can read the code and be able to tell my mechanic. I had spark plugs, coils of sone description that I believe are related with cylinders. But the OBD said cylinder 4. So the new Volvo mechanic (my last one was forced to shut down, sorry, hope this isn’t too many words &#128516 asked when it had been done, I was surprised to see it was as close as January of this year. He did it again anyway, reset the codes and within a week the dreaded cylinder 4 code came back. Taking it back in next week and next stop is injectors or something. Mine is V70 2.4l Base 2000 In actual fact, the mechanic mentioned injectors and because I’d researched the subject of my whole issue on this forum and Matthews Volvo Site, I knew I’d heard them mentioned and it gave me a boost of confidence to be able to trust the mechanic. I just typed in cylinder 4 and car model and year and hit return and see what pops up.