1998 s70 thermostat and ECT replacement 9186486 9144275

Post by **abscate** » 19 Nov 2025, 16:15

Been struggling with the stripped T40 on this b*stard for a few weeks. Finally popped off the fuel rail and banged the head loose with a chisel. Much easier on the 1999.

Big waves onthe beach

https://www.fcpeuro.com/products/volvo- ... 90-9186486

Post by **abscate** » 20 Nov 2025, 00:49

I will have to fix the connector on the ECT as it froze and broke while I made this repair. Good project over Thanksgiving

It’s been $7800 order year from FCP. I think I’m finished for 2025. I did order a fair amount on tariff scare which was a poor strategy but that’s on me. Gains in market far outstripped any savings from parts cost going up.

Post by **Grantkat** » 20 Nov 2025, 06:30

abscate, you arent the only one. I will confess I did the same on the Tariff scare. I have a sequoia and still have product coming in from Japan as a result. FCP got a great deal of my business as well.

Post by **wizechatmgr** » 21 Nov 2025, 11:22

Which model car does that Cat fit? =)

Post by **abscate** » 22 Nov 2025, 03:59

Does anyone have the engine side connector for a -1998 ECT harvested I can buy? I’m not sure I can save mine , worst case I’ll have to make a new one somehow.

Could it possibly be this one

https://www.fcpeuro.com/products/volvo- ... wE#reviews

I sure wish I had followed ErikV advice and done this instead…long torx driver

Agreed, it is the thermostat. A long torx driver is the key on those bolts, so the shaft points straight down into the recesses in the screw head, so you can seat it securely. I hold a long torx screwdriver in place with one hand and turn the handle with pliers in the other hand. Then just a typical routine works fine (spray penetrant, unscrew after 5 minutes). Don't waste even one second with WD-40 in this situation, it is near worthless as a penetrating oil. That's a typo from cn90, he probably means Liquid Wrench etc.

Maple syrup smell is a sign you should also check the heater core though I agree that it has nothing to do with the time it takes the car to heat up. Does the coolant level drop at all?

Post by **rolsen11** » 22 Nov 2025, 17:31

abscate wrote: ↑22 Nov 2025, 03:59 Does anyone have the engine side connector for a -1998 ECT harvested I can buy? I’m not sure I can save mine , worst case I’ll have to make a new one somehow.

Could it possibly be this one

https://www.fcpeuro.com/products/volvo- ... wE#reviews

I sure wish I had followed ErikV advice and done this instead…long torx driver

Agreed, it is the thermostat. A long torx driver is the key on those bolts, so the shaft points straight down into the recesses in the screw head, so you can seat it securely. I hold a long torx screwdriver in place with one hand and turn the handle with pliers in the other hand. Then just a typical routine works fine (spray penetrant, unscrew after 5 minutes). Don't waste even one second with WD-40 in this situation, it is near worthless as a penetrating oil. That's a typo from cn90, he probably means Liquid Wrench etc.

Maple syrup smell is a sign you should also check the heater core though I agree that it has nothing to do with the time it takes the car to heat up. Does the coolant level drop at all?

Part number 970755 appears to be the correct harness side connector for the ECT. Not sure yet of the part numbers for new terminals and wire seals though if you need them. You might just need to be careful removing the old ones.

Post by **abscate** » 24 Nov 2025, 08:58

Well, good news.

The sidelight connector on Shagg (1999) was listed as a two pole connector similar to the 1998 ECT so I harvested it and tried it. Might need a bit of plastic shaving but it fits well.

Looks like the radiator trigger connector, the sidelight connectors and the -1998 style ECT all work here

Post by **abscate** » 30 Nov 2025, 04:21

abscate wrote: ↑24 Nov 2025, 08:58 Well, good news.

The sidelight connector on Shagg (1999) was listed as a two pole connector similar to the 1998 ECT so I harvested it and tried it. Might need a bit of plastic shaving but it fits well.

Looks like the radiator trigger connector, the sidelight connectors and the -1998 style ECT all work here

This transplant, 1999 side light plug to 1998 ect connector, worked! Note that on 1999 the ECT connector goes to a standard Volvo squeeze and slide type which seals better than previous.