Potential Coolant Temperature issue

[Tedwud]

Hello,
I‘ve already mentioned this issue before in my newbie post. But on my drive to work this morning (about 10 miles, 20 minutes). The coolant temperature never went above 70C. When I got out of the car, engine running, I could hear the cooling fan was on. I have also noticed in the past on previous warm starts, the engine doesn’t start as ’normal’ with its usual kick, it’s more subdued. A few weeks ago, the car wouldn’t start at all when I stopped off at the shop, it just spun over. The only way I could get it started was by feathering the throttle, which would suggest to me it’s possibly over fuelling. On Wednesday, I replaced the coolant temp sensor, cooling fan resister and the auxiliary belt.
Any help Or suggestions would be greatly appreciated.

Ta

 

[mjheathcote]

I'd get a odb2 diagnostic plugged in first to see if any codes.
Regarding the cooling fan I recall one of the fans might be running all the time if you have the air conditioning switched on.
A subdued hot restart isn't that unusual, and I can't remember what causes this off hand, but is a known issue.

 

[Oneball]

Ignoring the not start, I don’t think you got an issue. It’s cold at the moment. On the motorway even in the summer my 3200 ran cool

When starting from cold they the secondary air system and increased idle makes it sound different.

If the AC is on the fan will run pretty much irrespective of engine temp

If you’ve had BMW, Porsche, Merc, Audi before they’re temp gauges are so damped and non-sensitive that the normal position actually accounts for about 20c

 

[Tedwud]

Thanks Mike, I plugged it in on Wednesday, no fault codes found. I’ll do a bit more digging for the hot restart.

 

[Zep]

Subdued start is most likely to be the carbon canister or purge valve. Does it happen after you have filled the tank? This is the vapour from the tank going through the purge system, giving you the rich mixture which affect the start.

 

[Tedwud]

Subdued start is most likely to be the carbon canister or purge valve. Does it happen after you have filled the tank? This is the vapour from the tank going through the purge system, giving you the rich mixture which affect the start.

Thank you, I’ll look in to that.
No, I haven’t particularly noticed the hot start issue after refuel and it‘s only not started once, where it needed some encouragement from the right foot.

 

[Zep]

Thank you, I’ll look in to that.
No, I haven’t particularly noticed the hot start issue after refuel and it‘s only not started once, where it needed some encouragement from the right foot.

If it doesn’t start with the strong blip of revs like when cold, this is probably the cause. Was exactly the same on my GS, changed the canister and it was back to normal. It did it a lot of the time, but more so after fueling.

 

[mjheathcote]

Subdued start is most likely to be the carbon canister or purge valve. Does it happen after you have filled the tank? This is the vapour from the tank going through the purge system, giving you the rich mixture which affect the start.

Yes that's it, it has happened to me a few times after refuel.

 

[doodlebug]

About 8 years ago, I had exactly this problem in my 4200, although it was intermittent. It did get so bad that the car wouldn't start for several minutes after the engine was warmed up and there was a strong smell of over-fuelling on trying to start it. I remember another member had exactly this fault and I told him my woes in getting it repaired but I'm not sure if his was fixed.

The initial consensus was a faulty engine temperature sensor. Lancaster's replaced it, which seemed to work for a bit, but because the fault was intermittent, it only 'worked' for a few days. Lancaster's suggested the part they fitted must be faulty so they replaced it again. The fault came back again.

I took it to an independent garage where they suggested the cooling fan being on all the time was normal if the air-conditioning is on, but that isn't the case at all as the operation of the fan was perfectly normal before the fault developed. It was only after they disconnected the air-conditioning control unit and seeing the fault was still present that they managed to trace the fault to a faulty gauge control unit. This is located in the binnacle housing the gauges. This gauge controller was replaced and the fault has never recurred.

 

[Tedwud]

Thank you for your replies. I’ll put it back on the diagnostic this week to see what the actual temp read out is. I got home from work this evening, temp never got above 70C again. Both fans running with A/C off. I left it an hour, went out to start it again, it didn’t start as ‘normal’ and both cooling fans came straight on. Something isn’t quite right.

 

[Tedwud]

About 8 years ago, I had exactly this problem in my 4200, although it was intermittent. It did get so bad that the car wouldn't start for several minutes after the engine was warmed up and there was a strong smell of over-fuelling on trying to start it. I remember another member had exactly this fault and I told him my woes in getting it repaired but I'm not sure if his was fixed.

The initial consensus was a faulty engine temperature sensor. Lancaster's replaced it, which seemed to work for a bit, but because the fault was intermittent, it only 'worked' for a few days. Lancaster's suggested the part they fitted must be faulty so they replaced it again. The fault came back again.

I took it to an independent garage where they suggested the cooling fan being on all the time was normal if the air-conditioning is on, but that isn't the case at all as the operation of the fan was perfectly normal before the fault developed. It was only after they disconnected the air-conditioning control unit and seeing the fault was still present that they managed to trace the fault to a faulty gauge control unit. This is located in the binnacle housing the gauges. This gauge controller was replaced and the fault has never recurred.

Thank you for your extensive reply Doodlebug. Is the gauge controller unit an independent unit or is it part of the instrument cluster ?

 

[doodlebug]

Thank you for your extensive reply Doodlebug. Is the gauge controller unit an independent unit or is it part of the instrument cluster ?

I'm not sure, Tedwud.
From memory, it didn't cost much for a Maserati part. Grimaldi in Halstead fixed it so Rob from there might remember the repair or maybe look on the Eurospares website.

 

[allandwf]

Thermostat possibly stuck open.

 

[doodlebug]

Thermostat possibly stuck open.

My car had EXACTLY the same symptoms as Tedwud described. It had two new engine temperature sensors, a new fan resistor and a new thermostat and the fault was still there.

Eventual replacement of the gauge controller fixed it.

 

[babel 101]

IT MAY BE THE THERMOTAT THAT IS HALF OPEN

 

[RJ237]

When I bought my coupe a couple of years ago it ran at 55-65 C unless I was stationary. After replacing the thermostat it did not drop below 85.
In traffic on a hot day with the AC on it's 93-95 C.

 

[Tedwud]

Thank you. New thermostat will delivered tomorrow and fitted this week. It’s certainly what i suspect to be the problem with the cooling issue. I’ll feed back when I’ve done it.

 

[doodlebug]

The only difference a new thermostat did for me was to empty my wallet. A faulty thermostat won't make the fans run continuously.

 

[Tedwud]

The only difference a new thermostat did for me was to empty my wallet. A faulty thermostat won't make the fans run continuously.

I know, but for £75, it’s worth trying. I saw a thread on here and the chap had a white GS with similar issues, it turned out to be his thermostat. It arrived today, so I’ll fit it on Friday and see what happens. I’ve done a bit of research but I’m struggling to find anything that resembles a gauge control unit but I’ll keep looking.

 

[doodlebug]

I know, but for £75, it’s worth trying. I saw a thread on here and the chap had a white GS with similar issues, it turned out to be his thermostat. It arrived today, so I’ll fit it on Friday and see what happens. I’ve done a bit of research but I’m struggling to find anything that resembles a gauge control unit but I’ll keep looking.

This is the part that Grimaldi replaced which cured the problems, item 1 (Part Number 196622) in the diagram below. I told you it was cheap for a Maserati part.

Grimaldi had also changed the thermostat earlier in the year but it made no difference.



I hope you get it fixed soon. It used to drive me nuts!