7 replies to this topic

[kopi]

Hi all. 

 

Have a '92 spi that overheats in traffic. Turns out the aux fan wasn't working and my mechanic suggested further to remove the thermostat. I live in the tropics, ambient temperatures at 26-32 °C all year so the theory was that the mini really didn't need a 88C thermostat for the warm up. 

 

Went for a drive tonight. Idle perfect. Warming up, took about 5 minutes (ambient temperature 26C) so not to bad. The drive though was something else. The engine seems very hesitant to rev and feels rough. The engine also seems to be "pulsing" if that makes sense. At a stop light, the idle is steady. But i can feel the entire car pulsing. When i gas it, the acceleration is definitely much rougher than before and the pulsing frequency quickens. It also almost sounds like the exhaust is huffing and puffing too much. 

 

Any thoughts? Can removing the thermostat mess things up so much? Or should I be looking somewhere else? Thanks all!

 

Best,

Kopi

 

*edit: the speedo cable was replaced. vacuum pipes etc was also recently replaced. 

Edited by kopi, 20 May 2016 - 03:27 PM.

[tmsmini]

Typically when removing a thermostat, a blanking sleeve is used to make sure coolant circulation remains correct.

http://www.minispare...|Back to search

 

I am not sure how this would work in an SPi with a sandwich plate.

 

In reality a thermostat does not make an engine run hotter once it is open, so I would disagree with the statement on the MS listing. An 82 thermostat is just as open as an 88 at full open. Even with a 26 degree temp, I would still use a working thermostat in an injected engine.

[Will16]

IIRC removing the thermostat can cause cylinders 3 and 4 to overheat locally as there is reduced flow.

[kopi]

Don't know how i missed the blanking sleeve! Thank you both. Minispares mentions that it is necessary to blank off the by-pass hose (not found on late heads). What's the best way to blank this off? (sorry for the noobish question)

 

The mini was driven a fair bit by my mechanic, to-and-from my place. He's a good guy but now i'm concerned about engine damage! I wonder if the symptoms i'm feeling now are a result of that. 

 

Edited by kopi, 20 May 2016 - 04:11 PM.

[tmsmini]

I don't think you would have caused damage at this point, just uneven cooling with hot spots.

I am not completely up to date on the SPi cooling system hose routing, so you may not have a bypass hose. Somewhere there are plugs sold for the purpose and then you need a non-bypass water pump.

 

I would still run the 88 C thermostat with an injected engine as you want it at running temp as soon as possible, if you have cooling issues at 26 C ambient, there is something else going on.

[kopi]

thanks tmsmini

 

i believe the primary cause of the overheating was a faulty aux fan connection which has since been fixed. Removing the thermostat was a suggested preventive measure. 

 

So the question remains - are the symptoms i'm facing (can't rev, ok idle, engine "pusles", blowing exhaust - almost brand new maniflows!) possible due to (1) no thermostat or (2) missing out a procedure somehow after replacing a snapped speedo cable? (1) does not seem very likely. And i'm not sure about (2). 

[Steve220]

If your car is not getting to temperature properly then it will run rough. You need to get a thermostat in there.

[absx2]

The very fist thing to do is put a new thermostat in !

A blowing exhaust will upset a SPI . The pulsing would be the injection system compensating for the bad fueling, possibly caused by the blowing exhaust. A manifold leak would throw the fueling out badly.

Check all the small vacuum pipes in and around the engine bay.

Check your hot and cold running sensors and connections,sorry I don`t know where they will be as I rarely touch injected minis.

Fixed my sisters Corsa with a £8 cold running sensor on the thermostat housing :)